Dissertations / Theses: 'Inorganic and solid state chemistry'

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Ruff, Philip William. "Structural aspects of certain inorganic solid-state materials." Thesis, University of Leicester, 1988. http://hdl.handle.net/2381/33879.

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An introduction to the theory of phase transitions is presented which includes both thermodynamic and structural treatments of phase transitions. A literature review of the role of vibrational spectroscopy in the investigation of phase transitions is given for the period covering 1978 to 1987. Full experimental procedures are outlined covering the design and use of the diamond anvil cell (d.a.c.) utilised in the experimental investigations undertaken in this work. The single crystal structure of Re(C0)5I has been determined by x-ray diffraction techniques, together with a structural comparison with the other members of the Re(C0)5X series (where X = Cl, Br). Following on from the above, a vibrational investigation of the M(C0)5X series (where M = Mn, Re; X = Cl, Br, I) is presented. An accompanying high-pressure Raman investigation of Re(CO)5I is also shown. The group I metal halate series MXO3 (where M = K, Na; X = Cl, Br) have been investigated by infrared and Raman spectroscopy. High-pressure data are available for some of the series. In continuation of earlier work a phase structural investigation, at high-pressure, of KCIO3 was performed using synchrotron radiation at the SRS, Daresbury.

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Fowkes, Amelia Jane. "High resolution powder neutron diffraction in solid state inorganic chemistry." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299525.

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Haghighat, Siavash. "Melt and solid state behaviour of polyolefin blends." Thesis, Loughborough University, 1990. https://dspace.lboro.ac.uk/2134/28165.

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Polymer–polymer blends are rapidly growing as an important resource for obtaining new and improved polymeric materials; and polyolefins are among the most widely used thermoplastics in the polymer industries due to their low cost, desirable physical properties and wide range of applications. For this reason several polyolefin polymers were melt blended and different experimental techniques were used to investigate their characteristics and their properties. The blends under investigation are reported in four chapters, following a literature survey and a description of experimental techniques.

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Al-Jowder, Osama Abdulla. "Vibrational spectroscopy of metal cluster compounds and solid state phenomena." Thesis, University of East Anglia, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304888.

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Mitchell, Martin R. "Investigation of structure and disorder in inorganic solids using solid-state NMR." Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/3367.

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The use of solid-state NMR and DFT calculations to study Y₂Sn[subscript(x)]Ti[subscript(2-x)]O₇, Y₂Sn[subscript(x)]Zr[subscript(2-x)]O₇ and Y₂Ti[subscript(x)]Zr[subscript(2-x)]O₇, materials with applications for the safe encapsulation of radioactive actinides is investigated. As a result of cation or anion disorder in these materials, NMR spectra are often complex and difficult to interpret. Therefore, an investigation using a range of NMR active nuclei and measurement of a variety of NMR parameters (isotropic chemical shift, δ[subscript(iso)]; span, Ω and quadrupolar coupling, C[subscript(Q)]) were used to provide a full and detailed picture of each material. The measurement of Ω in these disordered compounds with multiple resonances in the NMR spectra, required the use of 2D CSA-amplified PASS (CAPASS) experiments to enable the separation of each of the spinning sideband manifolds. An experimental assessment of the CAPASS experiment showed that although low ν₁/Ω[subscript(Hz)] ratios (as found in ⁸⁹Y NMR) resulted in distortions in the spectra obtained, a modified fitting procedure could be utilised to compensate for this fact, which allowed the accurate measurement of Ω. Despite the difficulties in acquiring the ⁸⁹Y NMR spectra, they were found to be the most informative of the NMR-active nuclei available. ¹¹⁹Sn NMR spectra, although much easier to acquire than ⁸⁹Y, were more complex and harder to analyse, owing to the overlapping resonances. Therefore, ¹¹⁹Sn NMR could only be used to confirm or support the results obtained using ⁸⁹Y NMR. Although ¹⁷O NMR was found to be useful, a full study could not be implemented due to the lack of ¹⁷O enriched samples; an area where future investigation may prove fruitful. Finally, [superscript(47/49)]Ti and ⁹¹Zr NMR spectra were found to be the most difficult to acquire due to their low receptivities and the quadrupolar broadened lineshapes, and as a result, little additional information was obtained. As a result of this analysis, for the Y₂Sn[subscript(x)]Ti[subscript(2-x)]O₇ pyrochlore solid solution, using primarily ⁸⁹Y δ[subscript(iso)] and Ω, and additionally confirmed with ¹¹⁹Sn δ[subscript(iso)], it was found that the Sn and Ti cations were randomly ordered throughout the B-sites. Additionally, ⁸⁹Y Ω could be used to obtain approximate Y-O[subscript(48f)] and Y-O[subscript(8b)] bond lengths for each type of Y environment. The study of Y₂Sn[subscript(x)]Zr[subscript(2-x)]O₇ using ⁸⁹Y NMR showed that although the end members were single phase, pyrochlore (Y₂Sn₂O₇) or defect fluorite (Y₂Zr₂O₇), the intermediate compositions were mostly two phase mixtures, consisting of an ordered pyrochlore (with an average formula of Y₂Sn₁.₈Zr₀.₂O₇) and a disordered phase, where the proportions of the pyrochlore and disordered phases decreased and increased, respectively, with the Zr content. Additionally, although the coordination states of the Y and Sn cations were easily determined using ⁸⁹Y and ¹¹⁹Sn NMR, respectively, the coordination states of the Zr cations could not be confirmed directly by ⁹¹Zr NMR. However, using indirect analysis from results obtained with ⁸⁹Y and ¹¹⁹Sn NMR, it was determined that 6 coordinate Zr was present in each composition, and it was always present in a greater proportion than 8 coordinate Zr. Finally, although ⁸⁹Y NMR spectra of Y₂Ti[subscript(x)]Zr[subscript(2-x)]O₇ were extremely difficult to analyse, it was tentatively proposed that they could be similar to Y₂Sn[subscript(x)]Zr[subscript(2-x)]O₇ due to some similarities observed between the spectra.

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Lowe, Mark Philip. "Solid state and solution studies of aminomethylphosphonic acids and their polyoxometallate conjugates." Thesis, University of Newcastle Upon Tyne, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336271.

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Furman, Joshua D. "Novel phosphors for solid state lighting." Thesis, University of Cambridge, 2010. https://www.repository.cam.ac.uk/handle/1810/228686.

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Solid state white light emitting diode lighting devices outperform conventional light sources in terms of lifetime, durability, and lumens per watt. However, the capital contribution is still to high to encourage widespread adoption. Furthermore, the colour from today's devices is unsuitable for general room illumination and thus new phosphor materials are needed. This dissertation will examine the synthesis of inorganic nanoparticles and the possibility of using hybrid inorganic-organic frameworks in the search for new lighting phosphors. Nanoparticles of the oxide compound yttrium aluminium garnet were synthesized using an emulsion technique, though it was found that the high temperature processing needed for good optical properties was not compatible with maintaining nanosized particles. In terms of hybrid framework phosphors, several aspects of this new area have been explored. The mechanical and optical properties of a dense cerium oxalate formate hybrid framework compound have been investigated. Its strength was found to be nearly as great as some classical ceramic compounds, and clearly robust enough for device applications. While the photoluminescence of the cerium oxalate formate was not suitable for solid state lighting, the impressive mechanical properties evaluated are expected to be valid for a wide range of dense inorganic-organic frameworks. A novel approach to solid state lighting phosphors was introduced by using ligand-based photoluminescence in hybrid frameworks. Novel frameworks were prepared using 9,10-anthraquinone-2,3-dicarboxylic acid in combination with calcium, manganese, nickel, and zinc. These compounds show excellent photoluminescent emission for use in solid state lighting applications, although the luminescence is quenched at room temperature due to dynamic effects. The excitation, while reaching the blue part of the spectrum, falls just short of what is needed for use today's devices. To address these issues, a second class of novel framework compounds was prepared using 9-fluorenone-2,7-dicarboxylic acid in combination with calcium, strontium, barium, cadmium, and manganese. They are more rigid structures and show good luminescence at room temperature with a photoluminescent excitation spectrum extending further into the blue than the anthraquinones. Additionally, quantum yield in the calcium fluorenone is nearly double that of its parent ligand, suggesting that there is an enhancement in luminescent properties as a result its inclusion in a framework structure. An explanation for the differences in efficiency between seemingly similar compounds are drawn from their compositions, crystal structures, photoluminescence, and specific heat properties. Finally, some structural and chemical targets for future hybrid phosphor development are identified based on the relationships identified in this work.

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Baughman, Jessi Alan. "Solid-State NMR Characterization of Polymeric and Inorganic Materials." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1428198096.

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Goodwin, Sarah L. "A solution and solid state study of polyiron complexes with carboxylate containing ligands." Thesis, University of East Anglia, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318023.

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Keates, Julian Mark. "Multinuclear solution and solid state nuclear magnetic resonance spectroscopic studies of selected organometallic compounds." Thesis, University of Sussex, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390081.

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Donakowski, Martin Daniel. "Syntheses, Local Environments, and Structure-Property Relationships of Solid- State Vanadium Oxide-Fluorides." Thesis, Northwestern University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3615500.

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Vanadium oxide-fluorides can exhibit properties of piezoelectricity, second harmonic generation (SHG) activity, electrochemical activity, and other phenomena. The first two properties derive from the second-order and Jahn-Teller distortions, respectively, of d⁰ and d¹ vanadium; the electrochemistry derives from the reduction of V^V to V^IV,III,II.

An examination of the immediate environment of a vanadium cation facilitates an understanding of how a cation influences the structure of a compound and its resulting properties. In the inorganic hydrate CuVOF₄(H₂O)₇, the CuVOF₄(H₂O)₆ basic-building unit (BBU) has a Λ-shape that compels polar packing in a structure that has SHG properties. The compound is a very rare example of a carbonless, SHG-active molecular crystal. Influences for its packing are reasoned with principles previously used within organic molecular crystallography.

The early transition metals (ETMs) of vanadium, niobium, and molybdenum within compounds of formulae K₁₀(M₂O_nF_11-n)X (M = V^V, Nb^V, n = 2, M = Mo^VI, n = 4; X = halide) show a related packing motif of Λ-shaped BBUs in different structures. Owing to the absence or presence of Λ-shaped BBUs, these heterotypical structures crystallize decidedly into SHG-inactive or SHG-active forms when M = V^V or M = Nb^V, Mo^VI, respectively. The future use and development of Λ-shaped BBUs within solid-state systems can result in SHG-active materials.

The material CuVOF₄(H₂O)₇ presents an interesting coordination: the late transition metal (LTM, Cu^II) coordinates solely to the oxide anion of the vanadyl cation owing to hard-soft acid-base (HSAB) properties. The materials Na₂[M(H₂O)₂][V₂O₄F₆] (M^II = Co, Ni, Cu) show the LTM coordinates solely to the oxide anions of the V^V cation while the alkali cation (Na^I) coordinates solely to the fluoride anions. These HSAB properties were used to generate layers of hard or soft cation/anion rich regions in the electrochemically-active double wolframite AgNa(VO₂F₂)₂.

These structure-property examinations of solid state vanadium oxide-fluorides are presented as principles for (i) fundamental understanding of ETM and BBU crystallographic environments, (ii) materials discovery for fundamental investigations, (iii) materials design, and (iv) materials for use in SHG, piezoelectric, and electrochemical processes.

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Moorhouse, Saul Joseph. "Studying the synthesis and reactivity of crystalline materials using in situ X-ray diffraction." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:73d3b464-d73a-467c-8428-c3ff0ddb7ffe.

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The use of in situ X-ray diffraction (XRD) to investigate reactions involving crystalline materials is the focus of the work described in this thesis. The development of procedures for probing chemical reactions in situ, and the application of this technique for studying in detail the mechanisms and kinetics of solid-state processes, is reported. The information in Chapter One provides a background to the in situ study of chemical reactions, with specific emphasis on the application of X-ray diffraction. Three distinct families of inorganic materials are introduced, including layered double hydroxides, Aurivillius phases, and metal-organic frameworks, and the relevance of each in contemporary technologies, is discussed. Chapter Two incorporates an account of the design, construction, and development of a chemical reaction furnace, the Oxford-Diamond In Situ Cell (ODISC), for the in situ study of solid-state reactions. The capabilities of this apparatus are discussed, including the efficient and controlled heating of samples to temperatures in excess of 1000 °C, optional sample stirring, and successful incorporation of a range of different sample vessels. Details of the implementation and optimisation of this equipment for use at Beamline I12 at the Diamond Light Source are provided. The synthesis and characterisation of a new series of ternary layered double hydroxides (LDHs) with general formula [M_xM’_2–xAl₈(OH)₂₄](NO₃)4•yH₂O (M, M’ = Zn, Ni or Co), is detailed in Chapter 3. It was discovered that these materials exhibit finely tuneable cation ratios in the intralayer regions. A study of the intercalation chemistry of this family is reported, including in situ energy-dispersive and angular-dispersive X-ray diffraction experiments. The chapter concludes with details of an in situ XRD investigation into the synthesis of these materials via direct reaction of metal salts with Al(OH)₃, which was observed to proceed in four stages. Chapter Four is concerned with the molten salt synthesis and characterisation of novel cation-doped compounds with the Aurivillius structure. The limited extent of substitution on the B-sites of the parent Bi5Ti3FeO15 material was observed to be highly dependent on the nature of the di- or tri-valent substituent. The impact of varying reaction conditions, such as dwell duration and nature of the molten salt, upon pure product formation is described. A comprehensive in situ XRD investigation into the molten salt synthesis of a novel doped Aurivillius phase is detailed in Chapter Five. A discussion of the synthesis mechanism, in addition to a description of the role of the molten salt in product formation, is provided. A brief in situ XRD study of the mechanism and kinetics of crystallisation of metal-organic frameworks (MOFs) is detailed in Chapter Six. The use of ion-exchanged polymer resin beads to direct the synthesis of MOFs is probed in real time, and the route to formation is compared to that for the conventional solvothermal technique. Experimental procedures pertaining to all of the above chapters are provided in Chapter Seven. Supplementary data are included in the Appendices.

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Adkins, Drew David Wayne. "Studies of BaO – La₂O₃ – MgO – MnO_n Compositional Space." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1440154953.

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Page, Samuel John. "The use of solid state NMR to monitor reactions and doping in inorganic materials." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/113823/.

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Solid state nuclear magnetic resonance (NMR) is a powerful probe of inorganic materials systems. Through carefully changing materials compositions and synthesis methods, the impact on the local structure can be investigated. These have been applied to three main materials sectors: Paramagnetic materials in NMR have traditionally suﬀered from poor resolution due to broadening experienced at the nuclei from localised unpaired electrons. In this work, a fast magic angle spinning (MAS) and low ﬁeld approach has been applied to these paramagnetic cathode materials to improve this resolution, and elucidate structural information from the investigated materials. The resolution gained from these techniques has been used to highlight diﬀerences observed in the 7Li shifts of lithium iron phosphate (LFP) produced by diﬀerent synthesis techniques. This was found to be related to the cell volume of the LiFePO4 phase. Furthermore, the investigation of V doped LFP by 7Li and 31P MAS NMR has resulted in the observation of many common impurities resulting from synthesis. Additionally, 31Presonances could be identiﬁed that were related to V near the phosphorus site, indicating successfully doping in some of the higher Li containing samples. Through 29Si and 17O MAS NMR, changes in the local structure between Ca and Zn doped Stöber nanoparticles are observed. Similarly to other Ca containing materials, incorporation of Ca into the Stöber network has been shown to disrupt Sibridging bonds promoting the formation of non-bridging bonds in the silica network. However, addition of Zn tells a diﬀerent story. This is ﬁrst observed in the static measurements, where incorporation of high amounts of Zn leads to no evidence of hydroxyls observed in the Stöber network. Whereas, high resolution transmission electron microscopy (HRTEM) and density functional theory (DFT) calculations conﬁrm the presence of crystalline Zn2SiO4 -II in the nanoparticles. Finally, activation of two series of synthetic sodium- and aluminium substituted calcium silicate hydrate (C-(N)-(A)-S-H) geopolymers are investigated. Increasing the CaO has been shown to increase the disorder of the silica network, and also to promote the increase of crystallinity of the systems through observation of calcium aluminate phases. Additionally, increasing the amount of aluminium relative to the silicon in the system, promotes more of these crystalline phases to form.

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Romero, Jennifer V. "A study on the formation of solid state nanoscale materials using polyhedral borane compounds." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2008. http://wwwlib.umi.com/cr/syr/main.

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Burkholder, Eric M. Zubieta Jon. "Solid state chemistry Structural influences of the binucleating transition metal/tetra-2-pyridylpyrazine complex on the molybdophosphonate and molybdoarsonate class of materials /." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2004. http://wwwlib.umi.com/cr/syr/main.

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Christendat, Dharamdat. "Synthesis, structural and solid-state, multinuclear magnetic resonance studies of some manganese and nickel complexes containing silicon, tin, lead and phosphorus ligands." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34928.

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A number of organometallic complexes involving manganese, bonded to silicon, tin, lead and phosphorus ligands, and nickel, bonded to various trialkylphosphine ligands, has been synthesized and their crystal structures, vibrational, and multinuclear magnetic resonance spectra have been obtained. The FT-IR and FT-Raman spectra of the manganese carbonyl compounds in the carbonyl region (2200--1850 cm--1) have been assigned. Solid-state, CP-MAS, 13C, 29Si, 31P, 117Sn, 119Sn and 207Pb NMR spectra of substituted pentacarbonylmanganese(I) and tetracarbonylmanganese(I) complexes feature asymmetric sextets, whereas those containing a group 14 (IVA) element bridging two pentacarbonylmanganese(I) moieties show asymmetric sextets. The uneven splitting arises from spin-spin coupling and second-order quadrupole-dipole effects, which are not eliminated by magic angle spinning. The solid-state NMR spectra of the manganese complexes have been analyzed to give the isotropic chemical shifts, the chemical shift tensors, one-bond spin-spin coupling constants, 55Mn nuclear quadrupole coupling constants, effective dipolar coupling constants and the anisotropies; in the spin-spin coupling for each complex. The results provide new insights into the relationship between spin-spin coupling and quadrupolar coupling in bimetallic complexes involving a quadrupole transition-metal and a spin-1/2 nucleus.
For the para-substituted triaryltin complexes, the 13C, 55Mn and 119Sn chemical shifts and one-bond spin-spin constants in solution show excellent correlations with pairs of substituent constants (sigmaI, sigmaR). However, there is no correlation of the chemical shifts or spin-spin coupling with either Hammett (sigmaP) or Taft (sigmaP o) constants or the Mn-Sn bond lengths, rMn-Sn. The results obtained from dual substituent parameter (DSP) analysis indicate that both resonance effects (sigmaR) and inductive effects (sigma I) are important in determining the NMR parameters.
Crystal structures and high-resolution solution and solid-state 31P NMR spectra were obtained for several dihalobis(trialkylphosphine)nickel(II) complexes. The crystal structures and NMR results indicate that these complexes are trans square-planar in the solid-state. The chemical shifts and shift tensors were obtained and found to vary with the electronic properties of the halogens. The 31P isotropic chemical shifts in the solution spectra of dibromo- and diiodiobis(tribenzylphosphine)nickel(II) are very different from those found for the solid-state, and chemical exchange effects were observed in all spectra. The mechanism of exchange appears to involve the formation of dimers with bridging halides.

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Wongariyakawee, Anchalee. "Novel layered double hydroxide chemistry for application in cement and other building materials." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:3670c777-c860-43a8-9cdc-5a7d2c87b71b.

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The investigation into the syntheses and the intercalations of LDHs is the focus of the work described in this thesis. An introduction to Layered Double Hydroxide (LDH) materials with an emphasis on the possible host lattices and to their applications is given in Chapter 1. The application of LDHs in cement including; history of cement, cement production process, and cement hydration is detailed. The synthesis of the Ga-doped Ca₂Al(OH)₆Cl•nH₂O LDHs (Ca₂Ga_xAl_(1–x)-Cl; where 0 < x < 1) via the co-precipitation method is reported in Chapter 2. The effect of doping Ga³⁺ on a parameter of Ca₂Ga_xAl_(1–x)-Cl was determined by using Vegard’s law and the correlation between a parameter and x value was derived. The intercalation of organic anions including; sodium styrene sulfonate, sodium butene dicarboxylate, sodium fumarate and ammonium poly(styrene sulfonate), in Ca₂Ga-Cl structure is described. The intercalation of lignosulfonate, naphthalene sulfonate and polycarboxylate into Ca₂Al(OH)₆NO₃·6H₂O (Ca₂Al-NO₃) is detailed in Chapter 3. The release behaviour for the LDHs and the kinetic modelling of the release are reported. The effects of these LDHs on cement hydration studied by using the in situ X-ray diffraction and the ultrasound shear-wave reflection are discussed. In Chapter 4, the synthesis of Ca₂Al(OH)₆NO₃·nH₂O via a non-ionic surfactant reverse microemulsion is reported. The effects of the amount and the solubility [Hydrophile-Lipophile Balance (HLB)] of non-ionic surfactant on the morphology and the size distribution of the LDHs are discussed. Two new nitrite intercalated Ca₂Al-LDHs [Ca₂Al(OH)₆NO₂·nH₂O] synthesised via both the co-precipitation and the reverse micro-emulsion method are detailed in Chapter 5. The hydration of Portland cement samples with additive nitrate- and nitrite-intercalated Ca₂Al-LDH made using co-precipitation is discussed. The synthesis of dispersed, uniform nanoplatelet [Ca₂Al(OH)₆DDS]•H₂O LDHs is reported in Chapter 6. The effects of the amount of the surfactant on the morphology and size distribution of the LDHs are described. The experimental procedures and characterising techniques employed in this study are listed in Chapter 7. Additional data are provided in the Appendices.

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Teng, Weijie Ruhlandt-Senge Karin. "From polymerization initiators to precursors for solid-state materials syntheses and structures of a series of molecular alkali and alkaline earth metal derivatives /." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2004. http://wwwlib.umi.com/cr/syr/main.

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Markland, Charles Ivor. "Novel aspects of layered double hydroxide chemistry." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:a3494026-6f43-4696-9ff4-7e3040fe7958.

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A number of different aspects of the chemistry of layered double hydroxides and similar materials have been explored in this thesis. The intercalation chemistry of these compounds, in both aqueous and mixed solutions, has been explored to synthesise over forty new hybrid layered materials by ion-exchange and rehydration-reconstruction methods. The host used include both previously-reported layered hydroxide compounds, and novel host materials synthesised by the extension of heterogeneous reactions of solid oxides. The synthesis of these novel materials provides insights into the factors that control the compatibility of the metal ions that may form hydrotalcite-like structures, in addition to providing compounds that may act as the precursors of catalysts and other functional materials. The new intercalation compounds synthesised show interlayer distances ranging from 7.1Å to 23.6Å, and demonstrate a variety of interlayer alignments as determined by powder X ray diffraction, dependent upon both the metallic content and the degree of hydration of the host compound. The anionic contents of the interlayer regions have been further characterised through infra-red spectroscopy, elemental microanalysis, solid-state NMR and thermogravimetric analysis techniques. The mechanism and kinetics of the release of the intercalated anions from the hosts have been studied in situations approximating their real-world applications, and the degree of release quantified by UV/Visible spectroscopy. Both the rates and mechanisms of anion release have been found to be dependent on the anion, the host, the temperature and the solution into which the anions are released; as such, the release timescales of the anions may be fined tuned through modifications of the host materials. In addition, an explanation has been suggested for the observed change in mechanism observed in instances of release in which the host compound is in only partial contact with the release medium.

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Stoltzfus, Matthew W. "Structure-property relationships in solid state materials a computational approach emphasizing chemical bonding /." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1190087366.

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Corkett, Alex J. "Structure, properties and chemistry of layered oxypnictides." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:d6740be0-42a1-408c-b063-cf5b267365aa.

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This thesis reports the synthesis and characterisation of the layered oxypnictides Sr₂MO₃FeAs (M = Sc, V and Cr) and CeOMnAs. In these materials the choice of transition metal cation at the tetrahedral site in the arsenide layer chiefly dictates the physical properties that are observed. The bulk of this work has focussed on the development of a new family of iron arsenide superconductor with the general formula Sr₂MO₃FeAs (M = Sc, V, Cr). This structure is comprised of anti-PbO-type [FeAs]^- layers which alternate with insulating [Sr₂MO₃]⁺ oxide fragments that resemble a portion of the K₂NiF₄ structure. In contrast to other FeAs parent materials, no member of the Sr₂MO₃FeAs family exhibits any strong evidence for long range Fe order or a tetragonal to orthorhombic distortion upon cooling. Attempts to electron and hole dope Sr₂ScO₃FeAs into the superconducting regime have as yet been unsuccessful. Although Sr₂ScO₃FeAs shows no evidence for Fe ordering, a checkerboard arrangement of Cr³⁺ spins in the ab-plane is observed below 40 K (k = (½, ½, 0)) analogous to that seen in Pr₂CuO₄. The partial substitution of Fe²⁺ (d⁶) by Co²⁺ (d⁷) in Sr₂CrO₃Fe_1-xCo_xAs has been shown to be a fruitful strategy for electron-doping this material into the superconducting regime with T_c maximised at 18 K in Sr₂CrO₃Fe_0.92Co_0.08As. It is also established that this substitution influences the ordering on the Cr sub-lattice with a doubling in the size of the magnetic cell along the c axis (k = (½, ½, ½)). Sr₂VO₃FeAs, a rare example of an “undoped” superconductor (T_c = 25 K), is shown to be electron-doped by mixed valence vanadium +3.13(5). Magnetometry measurements also reveal a series of magnetic transitions in Sr₂VO₃FeAs, however μSR and powder neutron diffraction studies suggest that this system is some way from commensurate long range order. In contrast to Sr₂CrO₃FeAs, electron-doping strategies in Sr₂VO₃FeAs have the effect of decreasing T_c and ultimately suppressing superconductivity entirely as Sr₂V_1-xTi_xO₃FeAs and Sr₂VO₃Fe_1-xCo_xAs materials are over electron-doped. Sr₂V_1-xMg_xO₃FeAs samples were also prepared, but rather than this strategy hole-doping the FeAs layer it preferentially oxidises vanadium towards V⁴⁺. This substitution also has a considerable effect on the superconducting critical temperature (T_c) which is raised as high as 31 K in Sr₂V_0.775Mg_0.225O₃FeAs. The isovalent substitution of Sr²⁺ by Ca²⁺ in Sr_2-xCa_xVO₃FeAs has been shown to strongly influence the superconducting properties of this material and a clear correlation between the evolution of T_c and the shape of the FeAs₄ tetrahedron has been established. These results demonstrate that superconductivity in iron-based superconductors is extremely sensitive to both electron count and the crystal structure. Finally, investigations into the manganese oxide arsenide CeOMnAs reveal room temperature ordering of Mn²⁺ spins and a spin reorientation transition of Mn moments at 36 K. This transition is concomitant with Ce ordering and an apparent weak structural distortion, demonstrating that f electrons are able to dictate the orientation of Mn moments.

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Perman, Jason Alexander. "Solid-State Synthesis of Imide Ligands for the Self-Assembly of Metal-Organic Materials." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3747.

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In this research project, reduction or complete elimination of organic solvents is explored in the synthesis of cyclic imides using a technique that brings reagents into favorable position to react. Cocrystal Controlled Solid-State Synthesis (C3Sy3), takes advantage of supramolecular interactions such as hydrogen bonding and π-π stacking to form a cocrystal which can sequential be heated to complete the condensation reaction and produce a desirable product. Twenty-five successful condensation reactions result in high and clean yield. C3Sy3 of cyclic imides with auxiliary hydrogen bonding moieties like carboxylic acid, carboxylate or pyridyl groups are amenable to form additional solid-state materials. These moieties are useful in forming coordinate covalent bonds with metal cations. Using these C3Sy3 synthesized molecules as ligands, various Metal-Organic Materials (MOMs) are self-assembled. These MOMs offer unique qualities owing to the properties of the cyclic imides. With the addition of accessible carbonyl groups, they may participate as hydrogen bond acceptors or hydrophilic groups. Various degrees of rotation of N-phenyl substituents around the imide plane allow for structural flexibility as a route to supramolecular isomers in MOMs. The ease in imide synthesis may allow the fast scale-up of these ligands for industrial application. Similar ligands are generally synthesized by cross-coupling or substitution reactions that require expensive catalyst and various organic solvents. Metal-organic materials are a class of compounds amenable to crystal engineering owing to the directional coordinate covalent bonds between metal or metal clusters and organic ligands. They are characterized by X-ray diffraction, spectroscopy, volumetric and gravimetric analysis. The C3Sy3 imides were used to construct various MOMs, from discrete nanostructures to extended 3-periodic frameworks that possess viable internal space for applications pertaining to porous materials. Structural characterization by single crystal X-ray diffraction and structure-function relations are addressed. Gas sorption experiments show that many of these materials are structurally robust and retain crystallinity after evacuation. Ion exchange and guest uptake experiments using the synthesized materials demonstrate their potential as agents for sequestration. The bottom-up synthesis of metal-organics materials is leading the field of crystal engineering with built-in properties, showing promise by combining attributes from both inorganic and organic components.

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24

Lee, Veronica. "A Combined Theoretical and Experimental Study on Deposition of Solid State Materials." Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1707299/.

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Deposition of solid state materials span a wide variety of methods and often utilize high energy sources such as plasmas and ultra-violet light resulting in a wide variety of characteristics and applications. A fundamental understanding is essential for furthering the applications of these materials which include catalysis, molecular filtration, electronics, sensing devices, and energy storage among others. A combination of experimental and theoretical work is presented here on several materials including 2D silicates on Pd, boron oxide, and vanadium oxynitride. Silicate formation under low energy electron microscopy demonstrate film permeability to oxygen, while ab initio molecular dynamics simulations reveal the possible initial mechanisms associated with the formation of boron oxide films during atomic layer deposition. Lastly, vanadium oxynitrides have shown preferential sputtering of N over O sites and theoretical binding energies serve as a guide for assigning experimental x-ray photoelectron spectra.

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25

Denis, Romero Fabio. "Topochemical synthesis of novel electronic materials." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:304da2ad-854f-4ff3-a5eb-7539eda15ab8.

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This investigation is based on the topochemical modification of three set of phases: Sr₃Co₂O₅Cl₂, SrO(Sr(Ru_0.5M_0.5)O₃)n (M = Ti, Mn, Fe; n = 1, 2, ∞), and SrO(SrVO₃)n (n = 1, 2, ∞). The topochemical reduction of Sr₃Co₂O₅Cl₂ using sodium hydride as a solid state reducing agent results in the formation of a reduced phase containing cobalt centres with an average oxidation state of +2 and an overall composition of Sr₃Co₂O₄Cl₂. The resulting material adopts a structure containing double sheets of square-planar corner-sharing CoO2 units separated by rock salt SrCl layers. Variable-temperature diffraction measurements reveal that these sheets undergo a cooperative Jahn-Teller distortion at T ~ 200 K due to unevenly filled degenerate (d_xy, d_yz) orbitals. This material adopts a magnetic structure in which the moments within each sheet are ordered antiferromagnetically, but the sheets are aligned ferromagnetically. An investigation was carried on the reduction behaviour of Ru-doped Sr(Ru_xFe_1-x)O₃. It was found that the reduction was non-topochemical for values of x > 0.5. For values of 0 < x < 0.5, no single phase precursor material could be formed. For the material with x = 0.5, reduction with CaH₂ produced a new phase with composition Sr(Ru_0.5Fe_0.5)O₂. This material is the first reported instance of Ru²⁺ in an extended transition metal oxide. DFT calculations reveal that, while the iron centres adopt a high-spin configuration, the ruthenium centres are in an intermediate-spin S = 1 configuration. Resulting competing magnetic interactions lead to frustration and lack of ordering. In order to further study the reduction behaviour of extended transition metal oxides containing ruthenium, the reduction of Sr₂(Ru_0.5Fe_0.5)O₄ and Sr₃(Ru_0.5Fe_0.5)₂O₇ was performed using CaH₂ as a solid state reducing agent. In these cases, reduction leads to segregation of the materials into multiple phases adopting closely related structures that differ mainly in their oxygen content. In these materials, the ruthenium centres are preferentially reduced, such that starting from materials containing Ru⁵⁺ and Fe³⁺, materials containing Ru^(3-δ)+ and Fe³⁺ are produced. Similarly, the low-temperature oxidation using CuF₂ as a solid state fluoride source was performed on materials with composition Sr3(Ru0.5M0.5)2O7 (M = Ti, Mn, Fe). In the case of M = Mn and Ti, materials with composition Sr₃(Ru_0.5Fe_0.5)₂O₇F₂ are produced in which the ruthenium centres are oxidised to Ru⁶⁺. For the M = Fe material, oxidation results in partial exchange of O for F and a material with composition Sr₃(Ru_0.5Fe_0.5)₂O_5.5F_3.5 in which the ruthenium centres are oxidised from +5 to +5.5 while the iron centres remain in a +3 oxidation state. While fluorination of the M = Ti leads to increasing itinerant electronic behaviour, fluorination of the M = Mn and Fe materials induces a twisting of the MX₆ octahedra that enables magnetic order to emerge at low temperatures. Finally, reaction of the SrO(SrVO₃)n (n = 1, 2, ∞) series of phases with CaH₂ results in the formation of phases with composition SrO(SrVO₂H)_n (n = 1, 2, ∞), the first examples of stoichiometric oxyhydride materials. SrVO₂H is magnetically ordered at room temperature, while the n = 1 and n = 2 materials order at 170 K and 240 K respectively. The high magnetic ordering temperature arises from strong interactions between (d_xy, d_yz) orbitals in a manner analogous to the reduced iron-containing phases SrO(SrFeO₂)_n.

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26

Reinsel, Anna Michele. "Spectroscopic Characterization of Organic and Inorganic Macromolecular Materials." University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1312823530.

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27

Wang, Chengle. "Controlled synthesis and properties of layered double hydroxides." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:80fc02cc-3e79-438f-9985-ae1663fc5554.

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The aims of this thesis are concerned with the synthesis of layered double hydroxide nanoparticles with controlled morphology and particle size distribution and an investigation of their physical properties. An introduction of layer double hydroxide chemistry, especially existing synthetic approaches, is reviewed in Chapter 1. Structural investigations, characterisation techniques, the properties and the applications of LDHs are discussed consecutively. The first successful synthesis of lithium aluminium nanorods using the hydrothermal treatment of a gibbsite precursor with a rod-like morphology is described in Chapter 2. The rod morphology is depicted using electron microscopy and confirmed by comparing refined X-ray diffraction patterns to a standard sample. Chapter 3 describes the application of reverse microemulsion method to prepare Co-Al and Ni-Al LDH nanoplatelets. The LDH particle sizes can be effectively controlled, and the structures of the nanoplatelets are investigated. The magnetic properties of the LDH nanoplatelets are dependent on the size of the nanoplatelets. A novel single component microemulsion system for the synthesis of LDHs is developed in Chapter 4. Mg-Al LDH nanoplatelets were successfully synthesised with precise particle size control. The factors affecting the formation of the microemulsions and the mechanism of the synthesis are discussed. Chapter 5 focuses on the applications of the novel single component microemulsion methods to prepare a range of LDHs with different metal combinations including Co-Al, Ni-Al, Zn-Al, Li-Al, Ca-Al, and Ni-Fe. This method proves very effective at controlling the particle sizes. The magnetic properties of the LDHs containing paramagnetic transition metal centres have been studied in detail. In Chapter 6, the DIFFaX program has been used to simulate the XRD patterns of layered structures. The factors influencing the XRD patterns in these materials have been systematically investigated including the effects of particle size, stacking faults, and disorder. The XRD patterns of materials described in previous chapters are simulated using the latest DIFFaX+ code in order to estimate the particle sizes and stacking sequences. The characterising techniques and the experimental details are listed in Chapter 7.

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28

Blandy, Jack. "Soft chemical control of layered oxychalcogenides." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:0fcc2604-0e0d-4206-a0aa-3fdcc611e357.

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The structure, magnetic behaviour and chemistry of layered oxychalcogenides of composition A₂MO₂X₂Ch₂ (where A = Sr, Ba; M = Mn, Co, Ni, Cu, Zn; X = Cu, Ag and Ch = S, Se, Te) has been investigated by the synthesis of new compounds of this type and control of the properties of these compounds by oxidative deintercalation of Cu/Ag. I₂ can be used to oxidatively deintercalate Cu from Sr₂MnO₂Cu_1.5S₂, forming Sr₂MnO₂Cu_1.33S₂, an incommensurately modulated compound, with a completely different Cu/vacancy ordering and antiferromagnetic ordering structure to the parent. This reaction is also probed in real-time, using in situ powder X-ray diffraction. Sr₂MnO₂Ag_1.5Se₂ was found to have an A-type magnetic ordering structure, similar to Sr₂MnO₂Cu_1.5Se₂. Sr₂MnO₂Cu_1.8Te₂ on the other hand with a lower Mn oxidation state shows only two-dimensional magnetic correlations, rather than long-range order. Extending the reaction with I₂ to several Co-containing analogues revealed that ~ 25% Ag could be removed from Sr₂CoO₂Ag₂Se₂, sufficient to observe a change in magnetic behaviour, from antiferromagnetic to ferromagnetic. By contrast only ~11% Cu can be deintercalated from Sr₂CoO₂Cu₂S₂ and even less (~5%) from Sr₂CoO₂Cu₂Se₂. Neutron diffraction was used to examine the resultant changes in magnetic ordering. The novel compounds Sr₂CuO₂Cu₂Se₂ and Ba₂CuO_2-xCu₂Se₂ are related by substitution of the alkali-earth metal, but while Sr₂CuO₂Cu₂Se₂ is a stoichiometric compound with metal-like character, Ba₂CuO_2-xCu₂Se₂ is an oxygen-deficient semiconductor, with tuneable oxygen content. Unusual features are observed in the magnetic susceptibility measurements of Sr₂NiO₂Cu₂Se₂ that appear unrelated to this compound's long-range magnetic ordering, as probed by neutron diffraction. Furthermore, unusual peak splitting is observed in low-temperature powder X-ray diffraction patterns of this compound; this may plausibly be due to a photon-induced effect arising from the use of a high-energy beamline; although further measurements are required to examine this. Overall the work shows the flexibility and range of behaviour exhibited by a series of the transition metal oxide chalcogenides.

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29

Pike, Sebastian David. "Investigating the chemistry of cationic rhodium bisphosphine complexes : comparing reactivity in the solid state with solution." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:413c8a57-0a5e-4e51-8874-e48db8079675.

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This thesis describes the synthesis and characterisation of a series of cationic rhodium bis-phosphine complexes. The reactivity of these new complexes in the solid-state and in solution is reported. In Chapter 2 the synthesis of a series of rhodium bis-phosphine diene complexes is presented and the reactions of these complexes with hydrogen in the solid-state are investigated. Several examples of zwitterionic complexes coordinating the [BAr^F4]^─ anion are produced by hydrogenation. A rare example of a sigma-alkane complex, [Rh(ⁱBu₂PCH₂CH₂PⁱBu₂)(eta²-_CH-eta²-_CH-NBA][BAr^F4]^─iBu₂PCH₂CH₂PⁱBu₂)(eta²-_CH-eta²-_CH-NBE][BAr^F4] may form as a short lived intermediate prior to the formation of the sigma-alkane complex. The temporal evolution of the solid-state hydrogenation reactions is monitored by powder X-ray diffraction methods. In Chapter 3 the C−X activation of various aryl halides using the [Rh(ⁱBu₂PCH₂CH₂PⁱBu₂)]⁺ fragment is reported. The 'ligand innocence' of the phosphine with respect to intramolecular C−H activation is also discussed. A rare example of C−X activation in the solid-state is presented, which shows the formation of an isomer that is not observed by analogous solution routes. Chapter 4 investigates solid-state ligand exchange reactions using ethene, butadiene, CO and NH3 gases. A solid-state transfer dehydrogenation reaction is reported within single crystals of [Rh(ⁱBu₂PCH₂CH₂PⁱBu₂)(C₂H₄)₂][BAr^F4]. H/D exchange of NH3 can also occur in the solid state in the bis-ammonia complex [Rh(ⁱBu₂PCH₂CH₂PⁱBu₂)(NH₃)₂][BAr^F4]. A variety of rhodium complexes are tested as heterogeneous catalysts for the hydrogenation of ethene and the isomerisation of butene. In Chapter 5 the binding affinity of a variety of fluorinated arenes to rhodium bis-phosphine fragments is presented using ESI-MS methods. The dependence upon the arene substituents, phosphine substituents and phosphine bite angle are discussed.

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30

Morrow, Ryan. "Competing Superexchange Interactions in Double Perovskite Osmates." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429787669.

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31

Alfurayj, Ibrahim A. "Solid-state Spin Equilibrium in Tetrakis(N,N'-diethylthiourea)nickel(II) dichloride, [Ni(detu)₄]Cl₂: Structural and Thermal Characterization." Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1435790988.

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32

Palmer, Erick J. "Synthesis, characterization and density functional theory investigations of tris-cyclopentadienyl compounds of zirconium and hafnium." The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1109969235.

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33

Pitcher, Michael J. "The structures and properties of layered pnictides and oxychalcogenides." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:2aa5e9e7-6519-45db-997e-4c747a5e8575.

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This work focuses principally on two compounds, CeCu_1-xOS and LiFeAs, which have related layered structures but exhibit radically different physical properties. The nature of the air sensitivity of the ZrCuSiAs-type oxysulfide CeCu_1-xOS has been investigated by neutron diffraction and magnetometry. It was found that this compound can be made fully stoichiometric, with structural and magnetic properties that are consistent with other LnCuOS compounds, indicating that this is a bona-fide Ce³⁺ compound. Upon air exposure, Cu ions are extruded from the sulfide layer to leave a Cu-deficient phase with contracted unit cell parameters and a diminished paramagnetic moment consistent with mixed-valence Ce^3+/4+.The extruded Cu forms CuO and can be re-inserted into the sulfide layer by heating under a reducing atmosphere. This explains the anomalous behaviour of CeCuOS reported throughout the literature and has implications for the behaviour of other layered Cu-sulfides with oxidisable cations. At low temperatures Cu-deficient CeCu_0.8OS was found to exhibit structural ordering of Cu⁺ ions and vacancies, resulting in a √5a x √5a basal expansion of the high-temperature unit cell. The layered iron arsenide LiFeAs was synthesised and found to be superconducting below 17 K. Joint XRD/NPD measurements showed unambiguously that the compound adopts the anti-PbFCl structure with Li ions in a square-pyramidal LiAs5 environment. No evidence was found for an orthorhombic structural distortion at low temperatures. Further diffraction experiments showed that the compound can be made with non-stoichiometric compositions Li_1-yFe_1-y for small values of y (<0.05), as Fe can be accommodated on the Li site. This type of non-stoichiometry was found to strongly inhibit superconductivity (which was quenched entirely when y>0.02). Three series of compounds of type LiFe_1-xM_xAs (M = Mn, Co, Ni) were synthesised and characterised struturally bu high-resolution XRD and/or NPD. Substitution by Co and Ni was found to cause a monotonic decrease in T_c, and Ni was found to be twice as effective at suppressing T_c as Co. MuSR measurements showed the penetration depth increasing with Co and Ni substitution, consisitent with the superconducting state becoming less robust. Substitution by Mn was found to strongly inhibit superconductivity, and this behaviour is reminiscent of the non-stoichiometric Li_1-yFe_1-yAs materials. The structures and superconducting properties of LiFeAs and NaFeAs were studied under high pressures. Equations of state were obtained for each compound. Hydrostatic pressure was found to distort of the FeAs₄ away from ideal tetrahedral geometry in both compounds. These changes caused a monotonic decrease in T_c in LiFeAs, but has a smaller and more complex effect on the T_c of NaFeAs. Furthermore, NaFeAs was found to undergo a structural transition above P = 22 GPa, but the high-pressure structure could not be solved and this will become a target for future work.

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34

Culligan, Scott D. "The crystal chemistry and hydrogen storage properties of light metal borohydrides." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:5a27d358-6b0d-4287-8b5d-f18304533dde.

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This work examines various light metal borohydrides, particularly those formed from group II metals, with the aim of understanding their fundamental physical properties and improving their hydrogen storage ability. The structure of a new phase (γ) of Mg(BH₄)₂ is reported and the decomposition is fully characterized in a combination of diffraction and thermogravimetric studies. The bulk properties of γ-Mg(BH₄)₂ are compared to those of an SiO₂ isostructure and probed by various neutron scattering techniques. Negative thermal expansion is observed at low temperatures and the material absorbs up to 1.5 moles of hydrogen gas to form one of the most gravimetrically hydrogen-dense materials ever reported. The structural evolution of Ca(BH₄)₂ under different synthetic conditions and external influences (e.g. temperature) is studied up until the material decomposes. The effects of various additives on group II metal borohydrides are also examined and the influence of each is justified by observing subtle structural changes in the mixed system via in situ synchrotron X-ray powder diffraction and ¹¹B NMR measurements.

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35

COKER, NATHAN LEE. "THE SYNTHESES AND CHARACTERIZATIONS OF THE VARIOUS SALTS OF [Au(SCN) ₂ ] ^-." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1053453898.

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36

Sandström, Malin. "Structural and solid state EMF studies of phases in the CaO–K2O–P2O5 system with relevance for biomass combustion." Doctoral thesis, Umeå universitet, Tillämpad fysik och elektronik, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-858.

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Fosfaters reaktioner i energiomvandlingsprocesser är kritisk för den generella processen som helhet, för askrelaterade problem, emissioner liksom för en effektiv och hållbar användning av askan. Denna avhandling är en sammanställning och diskussion med utgångspunkt i åtta artiklar som behandlar strukturella och termodynamiska studier på faser i CaO-K2O-P2O5-systemet, vilka är av relevans inom förbränning av biomassa. Målsättningen med denna avhandling var: i) att sammanställa och granska tillgängliga strukturella och termodynamiska data i CaO-K2O-P2O5-systemet samt att identifiera avsaknad av data, ii) att fylla i dessa luckor med grundläggande termodynamiska, strukturella och fasstabilitets studier samt iii) att visa på användning samt fördelarna med dessa nya data vid praktisk tillämpning. En initial litteraturundersökning i CaO-K2O-P2O5-systemet visade att det saknades både strukturella och termodynamiska data. När det gällde tillgängliga termodynamiska data var situationen särskilt otillfredsställande. Det fanns endast data för några kalcium– och kaliumfosfater med varierande tillförlitlighet. Situationen beträffande pulverröntgen för fasidentifiering var bättre, fast fördunklad av det faktum att strukturellt liknande fasövergångar ofta förekommer i det undersökta systemet. Däremot fattades det tillfredställande enkristallstrukturdata för ternära faser i det undersökta systemet. Enkristallröntgendiffraktion användes för att bestämma strukturerna för CaK2P2O7, CaKP3O9, Ca10K(PO4)7 och CaKPO4. Faserna CaK2P2O7 and CaKPO4 tillsammans med Ca3(PO4)2, KPO3 och K4P2O7 studerades med pulverröntgendiffraktion och termiska analysmetoder för att klargöra fasmodifikationer och övergångstemperaturer. Gibbs bildningsenergi bestämdes för Ca(PO3)2, Ca2P2O7, Ca3(PO4)2, Ca10K(PO4)7, CaK2P2O7, CaKPO4 och CaK4(PO4)2 med ems-metodik och yttriastabiliserad zirkonia som fast elektrolyt och Ni/Ni3P som hjälpsystem. Både de strukturella och termodynamiska data användes sedan vid analyser i ett förbrännningexperiment av olika sädesslag. Framtagna data användes både vid identifiering och även vid kvantifiering av bildade faser i biomassaresterna.
The behaviour of phosphates in thermochemical biomass conversion processes are critical for the general process chemistry, for ash related problems, for emissions as well as for an efficient, sustainable and beneficial use of the ash residues. This thesis is a summary and a discussion of eight papers dealing with structural and thermodynamical studies of phases in the CaO-K2O-P2O5 system, with relevance for biomass combustion. The objectives were: i) to compile and review the available structural and thermodynamical data of phases in the CaO-K2O-P2O5 system as well as to identify existing gaps in the field of these data, ii) to fill in as many as possible of the gaps by fundamental thermodynamic, structural and phase stability studies and iii) to demonstrate the uses and the benefits of the new data in practical applications. An initial review of the CaO-K2O-P2O5 system showed that both structural information and thermodynamic data were lacking. The situation regarding the available thermodynamic data was especially unsatisfactory, data could only be found for some few calcium phosphates and a few potassium phosphates with varying reliability. Concerning powder X-ray diffraction patterns for phase identification the situation was better, though obscured by the fact that structurally close related phase transitions often occur in the studied system. However, adequate single crystal structural data of ternary phases in the system was completely missing. Crystal structures of CaK2P2O7, CaKP3O9, Ca10K(PO4)7 and CaKPO4 were determined by single-crystal X-ray diffraction. The phases CaK2P2O7 and CaKPO4 were together with Ca3(PO4)2, KPO3 and K4P2O7, investigated by powder X-ray diffraction and thermal analysis to elucidate phase modifications and transitions temperatures. Gibbs standard energy of formation was determined for Ca(PO3)2, Ca2P2O7, Ca3(PO4)2, Ca10K(PO4)7, CaK2P2O7, CaKPO4 and CaK4(PO4)2 by solid state emf measurements with yttria stabilised zirconia as solid electrolyte and Ni/Ni3P as auxiliary solid couple. Both the structural and thermodynamical data were subsequently utilised in analysis of a combustion experiment of cereal grains. The data were also used to both identify and quantify the phases formed in biomass combustion residues.

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37

Smith, Christopher. "p-block hydrogen storage materials." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:6dd710a5-baf2-4fd2-918c-d1df97c229bf.

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The development of a clean hydrogen economy will aid a smooth transition from fossil fuels which is required to stem the environmental impact and economic instability caused by oil dependency. For vehicular application, in addition to being cheap and safe, a commercial hydrogen store must contain a certain weight percentage of hydrogen to provide a reasonable range (~300 miles). It must also be able to release hydrogen under near-ambient conditions (80-120°C) and have a reasonable cycling capacity (~1000 cycles). The primary motivation of this thesis is to gain a fundamental understanding into the sorption processes of hydrogen on carbon- and aluminium-based materials to improve their hydrogen storage capacity. The sorption processes of hydrogen on mechanically milled graphite have been investigated, primarily using Electron Spin Resonance Spectroscopy and Inelastic Neutron Scattering. An investigation into the storage properties of tetrahydroaluminates, primarily NaAlH₄ and LiAlH₄, is performed in the presence and absence of a catalyst, and a new phase of NaAlH₄ is observed prior to its decomposition. Variable temperature neutron and synchrotron diffraction, in conjunction with gravimetric and mass spectroscopy data were obtained for several mixtures of tetrahydroaluminates and alkali amides and the hydrogen desorption processes are shown to be quite different from the constituent materials. The structure of Ca(AlH₄)₂ has been experimentally determined for the first time and a complete set of equations describing its decomposition pathway is given.

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Seel, Andrew G. "Incoherent neutron scattering studies of select inorganic systems : I. Nuclear momentum measurements of multiple masses, II. The dynamics of coordinated ammonia in zeolite A." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:48e7a487-b203-46d6-9bb3-2866b1d98f1b.

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Spectroscopic measurements are detailed within this thesis, utilising incoherent neutron scattering to examine the dynamics of various condensed-matter systems, from nanosecond to sub-femtosecond timescales. The body of this work is divided into two distinct areas of research. I. Nuclear Momentum Measurements of Multiple Masses Deep inelastic neutron scattering (DINS) is used to probe the nuclear momentum distributions and kinetic energies of individual atomic species in sodium hydride (both in bulk and as nanoparticulates within a silica matrix), enriched lithium-7 fluoride and lithium tetra-ammoniate. Extension of DINS to examine heavier (M>4amu) nuclei is detailed, accomplished by the application of a simple stoichiometric fixing technique within the standard DINS theory and analysis protocols. The validity and accuracy of such simultaneous measurements are discussed. II. The Dynamics of Coordinated Ammonia in Zeolite A Inelastic neutron scattering (INS) and quasielastic neutron scattering (QENS) are utilised in the examination of vibrational and stochastic dynamics of the ammonia molecule, as coordinated to the internal surface of a zeolite host. Both sodium and copper-exchanged forms of zeolite-A are studied, with proton-weighted, low energy phonon-modes and rotational processes being observed and assigned.

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39

Bandara, Nilantha. "Guest intercalation into metal halide inorganic-organic layered perovskite hybrid solids and hydrothermal synthesis of tin oxide spheres." Master's thesis, Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-10312008-212759.

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40

Richard, Laura Amanda. "A study of the crystallographic, magnetic and electronic properties of selected ZrM2-H systems." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:276c59fe-cf45-42d2-a5a0-8c534c8b46bd.

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Dissolution of hydrogen into intermetallic compounds characteristically occurs at interstitial sites, causing little alteration to the base metal substructure but often bringing about substantial electronic and magnetic changes to the material. These hydrogen-induced alterations in the intermetallic hydrides are of interest both on a fundamental research level and in terms of technological applications; however, there exists no general theory as to how and why these alterations arise. The objective of this research is to elucidate to general effect of hydrogen on intermetallic compounds through the study of crystallographic, magnetic and electronic properties. An investigation has been carried out on the properties of three intermetallic compound - hydrogen systems of general formula ZrM₂, where M = V, Cr, Mn. All three compounds reversibly absorbed hydrogen with no change in crystal symmetry: powder diffraction studies showed that hydrogen was accommodated in interstitial sites of the existing metal sublattice via lattice expansion. The measurement of the magnetic properties of these systems was combined with the determination of conductivity and dielectric properties in order to describe the electronic e¤ects of hydrogen absorption. Despite the lack of signicant structural alteration in these systems, electron transfer between the metal sublattice and hydrogen may occur, as manifested in the appearance/disappearance of magnetic phenomena and the increase/decrease of electrical conductivity. Whilst the hydrogen addition in ZrM₂-H occurs simply via an expansion of the crystal structure, hydrogen does not act purely as null dilutant - there exist subtle electronic changes connected with the hydriding process as well.

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Royse, David M. "High density ammonia storage materials." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:2ccbf0d0-2fa7-4508-9544-565e47bfaddc.

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This Thesis considers the use of solid-state metal ammines as ammonia storage materials and endeavours to understand these materials on a fundamental chemical level. The ammines of LiBH₄, MgCl₂, MgBr₂, MgI₂ and Mg(BH₄)₂, are investigated. The structures of lithium borohydride ammines, Li(NH₃)_nBH₄ with n = 1, 2, 3 and 4 are solved using X-ray and neutron diffraction, vibrational spectroscopy, nuclear magnetic resonance, and first-principles calculations. The reversibility, bonding and ammonia storage properties of this system are discussed, and investigated using gravimetric analysis and vibrational spectroscopy. The ammines of magnesium halides are investigated using X-ray and neutron powder diffraction, gravimetric techniques, nuclear magnetic resonance, first-principles calculations and vibrational spectroscopy. Their disordered structures, bonding, and decomposition are discussed, and the trends in their properties are used to interpret the properties of other ammines. The ammines of magnesium borohydride are investigated using X-ray and neutron powder diffraction, gravimetric techniques, first-principles calculations and vibrational spectroscopy. The structure, decomposition and reversibility of Mg(NH₃)₆(BH₄)₂ as an ammonia store are presented. Throughout the Thesis and at the end of each Chapter the possibility of using these ammines as solid-state ammonia stores is discussed.

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Ryan, Katharine Rachel. "A study of ammonia borane and its derivatives." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:56384446-e80a-42f2-afdd-3c8a8ea33ce8.

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This thesis reports the investigation of molecular materials for hydrogen storage applications with a particular emphasis on alkali-metal amidoboranes. I have developed new routes for the synthesis of $alpha$-LiNH$_{2}$BH$_{3}$ and NaNH$_{2}$BH$_{3}$, and have studied their hydrogen storage properties by thermogravimetric analysis, variable temperature X-ray and neutron diffraction and inelastic neutron scattering. I report the synthesis and full structural characterization of two new materials, KNH$_{2}$BH$_{3}$ and $beta$-LiNH$_{2}$BH$_{3}$, and have performed initial studies on a tetragonal phase of a variant of LiNH$_{2}$BH$_{3}$ with a preliminary structure solution. I have also performed variable temperature neutron diffraction on ammonium borodeuteride, ND$_{4}$BD$_{4}$, and report the full structural characterisation of the three phases identified as a result of these measurements. Furthermore, variable temperature inelastic neutron scatting (INS) measurements were performed on ammonia borane, NH$_{3}$BH$_{3}$, and the results are discussed in terms of crystallographic phase changes.

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Cliffe, Matthew James. "Disorder and defects in functional molecular frameworks." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:cd827bc8-b3dd-4fda-bdb8-f0dc893d66c2.

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This Thesis explores the role of structural defects and disorder and their relationship to experimental data, with a particular emphasis on molecular framework materials. The question of how we can build atomistic models of amorphous materials from experimental data without needing to make system-specific assumptions is addressed. The role of 'structural invariance', i.e. the limited range of distinct local atomic environments within a material, as a restraint within reverse Monte Carlo refinement (RMC) is investigated. The operation of these invariance restraints operate is shown to be system-dependent and the challenges associated with effective refinement, e.g. configurational 'jamming', are also investigated. A generalisation to the 'structural simplicity', i.e. the simplest model, holding all else constant, is most likely to be correct. Three new metrics of structural simplicity are proposed: two intrinsically three-dimensional measures of local geometric invariance and one measure of local symmetry. These metrics are shown to robustly quantify the configurational quality. The ability of these metrics to act as effective restraints for the RMC refinement of amorphous materials is demonstrated by the construction of the first data-driven tetrahedral models of amorphous silicon. The role of defects and disorder within metal–organic frameworks (MOFs) is investigated through the canonical MOF UiO-66(Hf). Through a combination of techniques, including X-ray diffuse scattering, anomalous diffraction, total scattering and electron diffraction measurements, the existence of correlated metal-cluster absences in UiO-66(Hf) is demonstrated. Furthermore the ability to synthetically tune both the interactions and concentration of defects is shown. The thermomechanical properties of defective UiO-66(Hf) are also examined. UiO-66(Hf) is shown to rapidly densify by up to 5% (ΔV/V ) on ligand elimination. The resultant densified phase exhibits colossal (≥100MK^-1) volumetric negative thermal expansion (NTE); the largest reported value for any MOF. Finally, the capability to tune the physical properties of MOFs through defect incorporation is demonstrated through the defect-dependence of both the densification and the NTE.

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Pedra, Tellols José Miguel. "Procesado Láser de Materiales Cerámicos: Síntesis y modificación superficial." Doctoral thesis, Universitat Jaume I, 2015. http://hdl.handle.net/10803/669016.

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La tecnología láser es una técnica ampliamente utilizada en el procesado de materiales, especialmente en aquellos en los que se requieren la aplicación de tratamientos térmicos a altas temperaturas en áreas muy localizadas y con una gran precisión. En la presente tesis doctoral se muestran algunos ejemplos de aplicación de la radiación láser a materiales cerámicos de diversa naturaleza con tipos diferentes de procesado. Así, respecto a los tipos de procesado se han estudiado la fusión y la ablación:  la fusión se ha utilizado para la obtención de pigmentos cerámicos, tanto convencionales como nuevos, a partir de sus componentes precursores básicos (óxidos) y en ausencia de otros aditivos o catalizadores. Asimismo, también se ha utilizado para la síntesis de capas continuas de recubrimientos de tipo composite, con composiciones MTi-Al-O y M-Zr-Al-O (donde M = Ca, Sr, Ba) sobre soportes de alúmina sinterizada.  en cuanto a la ablación, se ha empleado para la mecanización de relieves sobre soportes cerámicos estándar típicos de la industria cerámica, como la pasta de porosa o el gres porcelánico. Se han estudiado tanto los productos finales como las partículas resultantes de la ablación, para determinar el rendimiento del proceso o la influencia de los diferentes parámetros en el proceso. Para finalizar, se muestran los resultados obtenidos de la combinación de ambos tipos de procesado aplicados a la fabricación de productos cerámicos tradicionales, como son los azulejos y baldosas. En este caso, se han ablacionado los soportes para conseguir los relieves deseados y, posteriormente, se ha aplicado el láser para conseguir la síntesis in situ de pigmentos directamente sobre el soporte cerámico, para realizar la decoración cromática del producto final.

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Ozdil, Yasemin. "Synthesis And Characterization Of Rare Earth Borophosphates." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/2/1219732/index.pdf.

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In this thesis, solid state reactions of Ln2O3, Y2O3, B2O3 and (NH4)2HPO4 were investigated to synthesize LnBP2O8 (Ln= Dy, Ho, Er) and YBP2O8 type of borophosphates which were not reported before. The products were analyzed by XRD, IR, DTA, SEM and EDX methods. In the first part of this thesis, synthesis of YBP2O8 through the solid state reaction of Y2O3 + 4(NH4)2HPO4 + B2O3 have been studied in the range 800-1140 °
C. Orthophosphates of Dysprosium, Holmium, Erbium and Yttrium have tetragonal xenotime (YPO4) or zircon (ZrSiO4) structure. Examination of X-ray powder diffraction data at 1140 º
C showed that the obtained structure was xenotime type together with weak BPO4 and Y(PO3)3 lines. The formula was calculated as YBxP1+xO4+4x through EDX and XRD data. The pattern was indexed in tetragonal system with the unit cell parameters of a= 6.8863, c= 6.016 Å
and s.g. is I41/amd. In the second part of this research, synthesis of LnBP2O8 through the solid state reaction of Ln2O3 + 4(NH4)2HPO4 + B2O3 (Ln= Dy, Ho, Er) have been studied in the range 800-1200 º
C. At 1200 º
C DyBP2O8 was obtained with tetragonal structure with the unit cell parameters of a= 6.905, c= 6.051 Å
and s.g. I41/amd. Using the same procedure HoBP2O8 was obtained at 1100-1200 º
C and the XRD pattern was indexed in tetragonal system with the unit cell parameters of a= 6.887, c= 6.024 Å
and s.g. I41/amd. In the structural analysis of ErBP2O8 obtained by the same reaction, the system was found as tetragonal and was indexed with a= 6.849, c= 5.998 Å
and s.g. I41/amd. Examination of the unit cell parameters with respect to ionic radius showed that the unit cell parameters decrease depending on the lanthanide contraction. The structures of the compounds obtained throughout this thesis were examined by IR spectroscopy and relation between the spectra and IR vibrational modes were established. The presence of bands due to BO4 in the final products revealed that Boron is in the solid solution with the tentative formula YBxP1+xO4+4x for Y and LnBP2O8 for lanthanides.

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King, Graham Missell. "Structural, Magnetic, and Electronic Studies of Complex Perovskites." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1262114272.

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Sandström, Malin. "Structural and solid state EMF studies of phases in the CaO–K₂O–P₂O₅ system with relevance for biomass combustion." Doctoral thesis, Umeå University, Applied Physics and Electronics, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-858.

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Fosfaters reaktioner i energiomvandlingsprocesser är kritisk för den generella processen som helhet, för askrelaterade problem, emissioner liksom för en effektiv och hållbar användning av askan.

Denna avhandling är en sammanställning och diskussion med utgångspunkt i åtta artiklar som behandlar strukturella och termodynamiska studier på faser i CaO-K₂O-P₂O₅-systemet, vilka är av relevans inom förbränning av biomassa. Målsättningen med denna avhandling var: i) att sammanställa och granska tillgängliga strukturella och termodynamiska data i CaO-K₂O-P₂O₅-systemet samt att identifiera avsaknad av data, ii) att fylla i dessa luckor med grundläggande termodynamiska, strukturella och fasstabilitets studier samt iii) att visa på användning samt fördelarna med dessa nya data vid praktisk tillämpning.

En initial litteraturundersökning i CaO-K₂O-P₂O₅-systemet visade att det saknades både strukturella och termodynamiska data. När det gällde tillgängliga termodynamiska data var situationen särskilt otillfredsställande. Det fanns endast data för några kalcium– och kaliumfosfater med varierande tillförlitlighet. Situationen beträffande pulverröntgen för fasidentifiering var bättre, fast fördunklad av det faktum att strukturellt liknande fasövergångar ofta förekommer i det undersökta systemet. Däremot fattades det tillfredställande enkristallstrukturdata för ternära faser i det undersökta systemet.

Enkristallröntgendiffraktion användes för att bestämma strukturerna för CaK₂P₂O₇, CaKP₃O₉, Ca₁₀K(PO₄)₇ och CaKPO₄. Faserna CaK₂P₂O₇ and CaKPO₄ tillsammans med Ca₃(PO₄)₂, KPO₃ och K₄P₂O₇ studerades med pulverröntgendiffraktion och termiska analysmetoder för att klargöra fasmodifikationer och övergångstemperaturer. Gibbs bildningsenergi bestämdes för Ca(PO₃)₂, Ca₂P₂O₇, Ca₃(PO₄)₂, Ca₁₀K(PO₄)₇, CaK₂P₂O₇, CaKPO₄ och CaK₄(PO₄)₂ med ems-metodik och yttriastabiliserad zirkonia som fast elektrolyt och Ni/Ni₃P som hjälpsystem. Både de strukturella och termodynamiska data användes sedan vid analyser i ett förbrännningexperiment av olika sädesslag. Framtagna data användes både vid identifiering och även vid kvantifiering av bildade faser i biomassaresterna.

The behaviour of phosphates in thermochemical biomass conversion processes are critical for the general process chemistry, for ash related problems, for emissions as well as for an efficient, sustainable and beneficial use of the ash residues.

This thesis is a summary and a discussion of eight papers dealing with structural and thermodynamical studies of phases in the CaO-K₂O-P₂O₅ system, with relevance for biomass combustion. The objectives were: i) to compile and review the available structural and thermodynamical data of phases in the CaO-K₂O-P₂O₅ system as well as to identify existing gaps in the field of these data, ii) to fill in as many as possible of the gaps by fundamental thermodynamic, structural and phase stability studies and iii) to demonstrate the uses and the benefits of the new data in practical applications.

An initial review of the CaO-K₂O-P₂O₅ system showed that both structural information and thermodynamic data were lacking. The situation regarding the available thermodynamic data was especially unsatisfactory, data could only be found for some few calcium phosphates and a few potassium phosphates with varying reliability. Concerning powder X-ray diffraction patterns for phase identification the situation was better, though obscured by the fact that structurally close related phase transitions often occur in the studied system. However, adequate single crystal structural data of ternary phases in the system was completely missing.

Crystal structures of CaK₂P₂O₇, CaKP₃O₉, Ca₁₀K(PO₄)₇ and CaKPO₄ were determined by single-crystal X-ray diffraction. The phases CaK₂P₂O₇ and CaKPO₄ were together with Ca₃(PO₄)₂, KPO₃ and K₄P₂O₇, investigated by powder X-ray diffraction and thermal analysis to elucidate phase modifications and transitions temperatures. Gibbs standard energy of formation was determined for Ca(PO₃)₂, Ca₂P₂O₇, Ca₃(PO₄)₂, Ca₁₀K(PO₄)₇, CaK₂P₂O₇, CaKPO₄ and CaK₄(PO₄)₂ by solid state emf measurements with yttria stabilised zirconia as solid electrolyte and Ni/Ni₃P as auxiliary solid couple. Both the structural and thermodynamical data were subsequently utilised in analysis of a combustion experiment of cereal grains. The data were also used to both identify and quantify the phases formed in biomass combustion residues.

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Nickels, Elizabeth Anne. "Structural and thermogravimetric studies of group I and II borohydrides." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:f18f8f7c-1837-4b96-b4bb-5f964e93899c.

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This thesis investigates the structure and thermal behaviour of LiBH4, NaBH4, KBH4, LiK(BH4)2, Ca(BH4)2 and Sr(BH4)2. LiK(BH4)2 is the first mixed alkali metal borohydride and was synthesised and characterised during this work. The crystal structures of these borohydrides were studied using variable temperature neutron and synchrotron X-ray diffraction. The synthesis of isotopically enriched samples of 7Li11BD4, Li11BD4, Na11BD4 and K11BD4 allowed high quality neutron diffraction data to be collected. Particular attention was paid to the exact geometry of the borohydride ions which were generally found to be perfect tetrahedra but with orientational disorder. New structures of Ca(BH4)2 were identified and the first crystal structure of Sr(BH4)2 was determined from synchrotron X-ray diffraction data. Solid state 11B NMR and Raman spectroscopy provided further information about the structure of these borohydrides. The thermal behaviour of the borohydrides was investigated using thermogravimetric analysis with mass spectrometry of the decomposition gas products. Hydrogen is the main decomposition gas product from all of these compounds but small amounts of B2H6 and BH3 were also detected during decomposition. Thermogravimetic analyses of Na11BD4 and K11BD4 were completed whilst collecting in-situ neutron diffraction data allowing information about structural changes and mass losses to be combined in order to better understand the decomposition process.

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Mishra, Rohan. "First Principles Study of Double Perovskites and Group III-V Compounds." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1345489862.

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Avala, Usha Kranthi. "Ionic Conductivity in Non-Ionic Compounds." TopSCHOLAR®, 2013. http://digitalcommons.wku.edu/theses/1279.

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The main objective of this work is to investigate the ionic conductivity of the drugs under certain conditions and also to compare the ionic conductivities of drugs determined by single surface sensors and parallel plate sensors. The ionic conductivity of various materials at their pre-melt and melt states are studied in order to further study a recently discovered phenomenon. Polar solids like Lidocaine, Ketoconazole, Procainamide and Nifedipine were examined in this study. Experimental studies show an increase in ionic conductivity in both pre-melt (20 -30 °C below melting temperature) and melt transition regions. Results of ionic conductivity of both parallel plate and single surface sensor at different frequencies are compared. At 1000 Hz, all the samples show an increase in ionic conductivity with both parallel plate and single surface sensor, but at 0.1 Hz frequency, no increase in ionic conductivity is observed with parallel plate sensor except for Nifedipine.

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Dissertations / Theses on the topic 'Inorganic and solid state chemistry'

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