Dissertations / Theses: 'Crystal structure of metals'

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Ponnada, Pradeepthi. "Crystal Structure Determination and Spectral Characterization of Dipeptides with Metals." Youngstown State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1343762067.

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Day, S. "Neutron and optical spectroscopy of alkaline earth metals." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234944.

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Eng, Hank W. "The crystal and electronic structures of oxides containing d0 transition metals in octahedral coordination." Connect to this title online, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1070570079.

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Thesis (Ph. D.)--Ohio State University, 2003.
Title from first page of PDF file. Document formatted into pages; contains xx, 180 p.; also includes graphics. Includes bibliographical references (p. 139-145).

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Kauser, N. "Low temperature anomalies in plastic response of crystalline materials with special reference to dilute solid solutions." Thesis, Brunel University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233340.

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5

Belot, Céline. "Synthesis, crystal structure and physico-chemical studies on thienyl-substituted alkoxides of the rare earth metals." Besançon, 2009. http://www.theses.fr/2009BESA2016.

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Ce travail porte sur la synthèse, la détermination des structures cristallographiques, l'étude des propriétés électrochimiques et la luminescence de méthoxydes contenant des groupements thiophéniques de métaux alcalins, d' étain(II) et de terres rares. La première partie est consacrée à la synthèse et aux études RMN et cristallographiques des nouveaux composés. Afin de corréler les effets structuraux et stéréoélectroniques sur la géométrie moléculaire, une série d'alcoxydes métalliques a été préparée. La seconde partie traite des propriétés électrochimiques des composés. Les voltammogrammes cycliques sont dominés par la vague d'oxydation des unités thiophéniques. Aucune réduction ou oxydation due aux centres métalliques n'a été constatée. Contrairement aux autres composés, après cyclage de la rampe de potentiels, la formation d'un film électroactif a été observée dans le cas des produits HO-C(CgHsSV3 (1), {Nd[OC(CgHsS2)3]3(thf)3}. 4 thf(10) et Er[OC(CgHsS2)3]3(thf) (11). La troisième partie concerne les propriétés de luminescence des produits. Les spectres d'absorption UV -Vis sont dominés par les ligands organiques. Les spectres d'émission des composés du potassium, sodium et yttrium révèlent de larges bandes attribuées aux transitions [Py*→Py]des groupements aromatiques. En outre, les spectres de luminescence des alcoxydes de Nd3+ et de Sm3+ mettent en évidence un transfert d'énergie (effet d'antenne) entre le ligand et le lanthanide
The present work focuses on the synthesis, crystal structure determination, electrochemical and luminescence studies of thienyl-substituted methoxides of alkali, tin(II) and rare earth metals. The first part is devoted to the synthesis, NMR and crystallographic investigations of the new products. To correlate structural and stereoelectronic effects on the molecular geometry, a series of rare earth metal alkoxides was prepared. The second part deals on the electrochemical properties of the novel compounds. The cyclic voltammograms are dominated by the oxidation wave of the thiophene groups. No reduction or oxidation of the metal centres bas been noticed. Contrarily to the other compounds, the repetitive cycling ofpotentials ofHO-C(CgHsS2)3 (1), {Nd[OC(CgHsS2)3]3(thf)3}. Thf (10) and Er[OC(CgHsS2)3]3(thf) (11) leads to the formation of electroactive polymeric film. The third part concerns the luminescence properties of the novel compounds. The UV-Vis absorption spectra are dominated by the organic ligands. The emission spectra of the potassium, sodium and yttrium compounds reveal broad bands attributed to the [Py* → Py] transitions of the aromatic ligands. Furthermore, the luminescence spectra of the Nd3+ and Sm3+ alkoxides exhibit an energy transfer ("antenna effect") from the Iigand to the lanthanide centre

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Ovchinnikov, Alexander. "Nitridomanganates of alkaline-earth metals." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-215891.

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The main goal of the present work was the synthesis of alkaline-earth nitridomanganates (AExMnyNz) with extended anionic structures and the characterization of their electronic and magnetic properties. Up to now, only compounds with isolated nitridomanganate anions have been reported in the discussed ternary systems. A systematic exploratory synthesis, employing high-temperature treatment of AE nitrides and Mn under controlled N2 pressure, yielded more than ten new nitridomanganates. Their crystal structures contain anionic building blocks of different dimensionalities, ranging from isolated species to three-dimensional frameworks. In general, the formation of Mn-rich compositions was found to be driven by the emergence of Mn-Mn interactions, which creates a link between nitridometalates and transition-metal-rich binary nitrides. The obtained nitridomanganates display a plethora of interesting phenomena, such as large spin-orbit coupling, magnetic frustration, quenching of magnetism due to Mn-Mn interactions, and metal-insulator transition.

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Chan, Eric J. "Structural systematics of complexes of lanthanoid picrates with unidentate O-donor ligands and other related arrays." University of Western Australia. School of Biomedical, Biomolecular and Chemical Sciences, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0075.

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Structures as determined by single crystal X-ray methods for lanthanoid(III) compounds for series of simple homoleptic species with diverse ligands frequently display variations entailing a diminution in coordination number (‘C.N.’), a consequence of the variation in the size of the atoms/ions due to the ‘lanthanoid contraction’. A change from C.N. nine to eight is common, clearly separating compounds of the light/‘early’ or heavy/‘later’ metal atoms. Earlier work on the complexes of the lanthanoid(III) picrates arose out of the exploration of simple reagents which might usefully exploit lanthanoid ion properties for purposes such as solvent extraction. They are also of potential synthetic utility because of their relatively high solubility in apolar solvents. This thesis encompasses a systematic structural study of hydrated lanthanoid picrate complexes (including those of yttrium) with a selection of dipolar aprotic solvent ligands, namely trimethylphosphate (‘tmp’), dimethylsulfoxide (‘dmso’), hexamethylphosphoramide (‘hmpa’), N,N´-dimethylacetamide (‘dma’), N-methylpyrrolidinone (‘nmp’) and octamethylpyrophosphoramide (‘ompa’), all liquids at room temperature and all unidentate, with the exception of ompa which can be considered in some cases to behave as the equivalent of two unidentate ligands, in others as a chelate. Structures of adducts of these ligands with scandium picrate are also included in order to gain further insight into the coordination behavior of the totality of the group ‘3’ transition metals, and, for similar reasons, a study of the structures of complexes of Eu(dipivaloylmethanide)3 with the same (solvent) ligands as a ‘baseline’. In the course of these studies, hydrolysis of the aprotic solvent trimethylphosphate was found to lead to novel adducts of the dimethylphosphate (‘dmp’) ligand; the introduction of polycyclic aromatic nitrogen base ligand complexes resulted in further novel mixed ligand compounds, supplemented by a study of protonated base picrate salts. This work aims not only to establish structural ‘domains of existence’ with a concomitant consideration of the associated stereochemistry for these related series of rare earth complexes, but, also, to enhance our understanding of metal ion solvation and the interactions of aromatic groups within these types of crystal structures.

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Koedtruad, Anucha. "SYNTHESIS OF NOVEL METAL HALIDES AND THEIR STRUCTURE-PROPERTY RELATIONS." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263484.

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Liu, Hui-Ping. "Magnetic ordering and crystal structure in selected transition-metal compounds /." Uppsala : Acta Universitatis Upsaliensis, 1999. http://catalogue.bnf.fr/ark:/12148/cb402057270.

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Lyle, Matthew John. "Crystal structure prediction and its application to novel metal oxides." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708224.

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11

Clough, Andrew James. "Synthesis and crystal structure determination of novel lithium metal-organic frameworks." Thesis, California State University, Long Beach, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1524184.

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In this thesis, three new lithium homometallic metal-organic frameworks are discussed. An introduction to lightweight metal-organic framework is given, followed by a detailed analysis of each new structure's topology, composition, novel secondary building units, and potential for gas adsorption. Special attention is given to the formation of new lithium secondary building units and the synthetic conditions that create them. These novel secondary building units are discussed in the context of the current lithium metal-organic framework literature, and compared when appropriate to known structures. Crystallography data is also discussed, with an emphasis on the connectivity of these lithium secondary building units.

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12

Abrams, Nicola Elaine. "The structure & desorption of molecular species from single crystal metal surfaces." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387862.

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13

Bucar, Dejan-Kresimir. "Crystal engineering of organic and metal-organic solids: design, structure and properties." Diss., University of Iowa, 2010. https://ir.uiowa.edu/etd/3435.

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Crystal engineering has recently emerged as a method of choice for the design and the construction of functional materials. Solid-state synthesis, of the most commonly studied aspects of crystal engineering, has been shown to provide access to molecular targets that are hardly obtainable using principles of conventional (i.e. solution-based) organic synthesis. Reactions in the solid state are, however, not routinely used in organic synthetic chemistry. The scarce use of solid-state reactions can be attributed to the difficulty of predicting molecular arrangements in the solid state, as well as to the lack of methodologies to control crystal packing. Template-directed solid-state synthesis is a recently developed modus operandi that enables control over reactivity within multi-component crystals. The thesis is focused on the application of template-directed solid-state approach to [2+2] photocycloaddition reactions in the solid state, as well as on the understanding of intermolecular interactions in crystals. Synthetic templates have been utilized to construct cocrystals that enable a class of hitherto underdeveloped organic solid-state reactions, namely [2+2] cross-photoaddition reactions. In addition, products derived form templated solid state reactions, namely tetrapyridylcyclobutanes, have been utilized to generate exceptional materials, such as thixothropic hydrogels based on nano-dimensional metal-organic particles. The utility of crystal engineering has also been expanded to the nanoscience and the development of nanomaterials. A crystallization method for the preparation of nano-dimensional cocrystals has been developed. The method has been shown to enable single-crystal-to-single-crystal [2+2] photodimerizations of olefins. In addition, nano-dimensional cocrystals have been shown to exhibit distinctive mechanical properties upon single-crystal-to-single-crystal transformations. In addition to solid-state reactions and materials derived therefrom, we systematically studied hierarchies of supramolecular synthons in pharmaceutical cocrystals comprised of multi-functional molecules. Pharmaceutical cocrystals have been recently shown to exhibit physical properties superior to those of parent drugs. Our studies involved xanthine alkaloids as pharmaceutical agents and a series of hydroxylated benzoic acids as cocrystal formers. Synthon hierarchies have been established for three xanthine alkaloids. We also discovered pharmaceutical salts that formed where cocrystallization was expected to occur. Reasons contributing to such unexpected salt formation were investigated using X-ray crystallography and computational methods. The established synthon hierarchies are expected to contribute to a better understanding of self-assembly processes in cocrystals that is crucial for the development of state-of-art drugs, and the design of organic reactions in the solid state.

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Salazar, Lupe E. Pulcha. "Lower rim calix[4]arene derivatives and their complexes with univalent cations : solution, complexation and X-ray diffraction studies." Thesis, University of Surrey, 2001. http://epubs.surrey.ac.uk/843331/.

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Following an introoduction on calixarene chemistry and their metal-ion complexes including some of their applications, the aims of the work are described. Thus, the first part of this thesis concerns the detemination of the standard enthalpies of solution, sH°, of new lithium and sodiimi 1:1 electrolytes based on eth p=tert-butycalix[4]arene tetraethanoate containing various anions in acetonitrile at 298.15 K. Using these data in conjunction with previously reported sH° values for the free metal-ion salts and the ligand and standard enthalpies of complexation, cH°H° of allcali-metal cations (Li+ and Na+) and the calix[4]arene ester in the same solvent, standard enthalpies of coordination, coordH° referred to the process in which the reactants and the product are in the solid stated were calculated. The anion effect on the coordination process was determined. The second part of this thesis is related to an investigation on the solution properties of pyridinocalix[4]arenes and their metal-ion complexes. Transfer Gibbs energies of geometrical isomers of pyridinocalix[4]arenes from acetonitrile to various solvents reflect that these ligands undergo selective solvation in the various solvents but these cannot be correlated with any single solvent property. The complexing ability of 5,11,17,23 - tetra - tert - butyl[25,26,27,28 - tetrakis (2-pyridyhnethyl) oxy]- calix[4]arene for metal cations was investigated by a variety of techniques. Thus 1H NMR studies were performed to obtain information about the active sites of the ligand in its interaction with metal cations. Conductance measurements were used to establish the composition of the metal-ion complexes in dipolar aprotic media. Potentiometric and calorimetric measurements were performed to derive the thermodynamics associated with the complexation process in acetonitrile and benzonitrile. Based on stability constant data, two metal-ion complexes were isolated. The crystal structure of the sodium and acetonitrile complex of 5,11,17,23- tetra- tert- butyl[25,26,27,28 - tetrakis (2-pyiidylmethyl)oxy] calix[4] arene solved by X-ray diffraction studies shows three different complexes in the lattice, two sited on a fourfold axis and a third one on a twofold axis where all ligands exhibit a 'cone' conformation and the sodium ion is encapsulated in their hydrophilic pockets with their hydrophobic cavities filled with an acetonitrile molecule. The crystal structure of the 1:1 monoacetonitrile and silver complex of the 2-pyridyl derivative with the perchlorate ion as the counter ion shows the macrocycle sited on a fourfold symmetry axis. The presence of acetonitrile in the hydrophobic cavity of the ligand is also found. The silver cation is encapsulated in the hydrophilic cavity through the ethereal oxygens and the pyridinic nitrogens. Conclusions and suggestions for furthur research in this area are given.

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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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Chen, Vanessa Wen Hsing. "Magnetic and structural studies of amine inclusion complexes of metal oxyhalides." Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314370.

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McManus, Gregory J. "Structural diversity in metal-organic materials." [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002596.

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Zheng, Keqin. "Design and Construction of Metallo-Supramolecular Terpyridine Possessing Higher Order Structure." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1375283764.

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19

Higgins, Daniel Louis. "The response of metals with different crystal structures to high strain rate loading and other mechanical tests." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7724/.

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The effect of cold-rolling prior to shock loading was investigated in copper and tantalum. Annealed copper was shocked at a peak pressure of 5.08GPa; cold-rolled copper was shocked at peak pressures of 5.87GPa, 5.96GPa and 9.60GPa; as-received tantalum was shock loaded at a peak pressure of 7.20GPa, and cold-rolled tantalum was shocked at a peak pressure of 7.20GPa. The microstructures of the materials were investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the mechanical responses were investigated using compression and hardness testing. The effect of varying temperature and strain rate on tantalum during compression was investigated. Tantalum was compressed at 20°C at 10⁻³s⁻¹, 10⁻¹s⁻¹ and 2x10³s⁻¹, and at 10⁻¹s⁻¹ at -40°C and 170°C. Quasi-static compression tests applied 70% strain to the samples and the higher strain rate sample, compressed by Split Hopkinson Pressure Bar (SHPB), was compressed to 19% strain. The microstructures of the materials were investigated using (SEM) and (TEM), and the mechanical responses were investigated using hardness and compression testing. The microstructures of adiabatic shear bands (ASBs) produced by firing a shaped projectile from a single stage gas gun to cause the collapse of a thick-walled cylinder (TWC). The propagation of the ASBs along the cylindrical axis of the TWC was Also investigated. The microstructure was investigated using (SEM), (TEM) and scanning transmission electron microscopy (STEM).

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Hossain, A. "Synthesis, crystal structure and properties of complex oxides with the perovskite structure based on neodymium, alkaline earth and 3d-transition metals : dissertation for the degree of candidate of chemical sciences : 02.00.04." Thesis, б. и, 2019. http://hdl.handle.net/10995/82032.

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Münch, Annika. "Klassifizierung polarer Metall-Kohlenstoff-Bindungen in hauptgruppenmetallorganischen Verbindungen mittels experimenteller Elektronendichteanalyse." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-14B9-4.

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Butterfield, Martin Thomas. "Surface structure of ultrathin metal films deposited on copper single crystals." Thesis, Loughborough University, 2000. https://dspace.lboro.ac.uk/2134/33132.

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Ultrathin films of Cobalt, Iron and Manganese have been thennally evaporated onto an fcc Copper (111) single crystal substrate and investigated using a variety of surface structural teclmiques. The small lattice mismatch between these metals and the Cu (111) substrate make them an ideal candidate for the study of the phenomena of pseudomorphic film growth. This is important for the understanding of the close relationship between film structure and magnetic properties. Growing films with the structure of their substrate rather than their bulk phase may provide an opportunity to grow materials with novel physical and magnetic properties, and hence new technological applications. Both Cobalt and Iron have been found to initially maintain a registry with the fee Cu (111) surface in a manner consistent with pseudomorphic growth. This growth is complicated by island rather than layer-by-layer growth in the initials stages of the film. In both cases a change in the structure of the film seems to occur at a point where the coalescence of islands in the film may be expected to occur. When the film does change structure they do not form a perfect over-layer with the structure of their bulk counterpart. The films do contain a number of features representative of the bulk phase but also contain considerable disorder and possibly remnants of fcc (111) structure. The order present in these films can be greatly improved by annealing. Manganese appears to grow with an fee Mn (111) lattice spacing and there is no sign of a change in structure in films of up to 4.61 ML thick. The gradual deposition and annealing of a film to 300°C, with a total deposition time the same as that for a 1 ML thick film, causes a surface reconstruction to occur that is apparent in a R30° (√3×√3) LEED pattern. This is attributed to the formation of a surface alloy, which is also supported by the local expansion of the Cu lattice in the (111) direction.

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23

Doert, Thomas. "Quadratische Netze, Fehlstellen und Modulationen - Strukturchemie von Polyseleniden und Selenidditelluriden der Lanthanoidmetalle." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2006. http://nbn-resolving.de/urn:nbn:de:swb:14-1161601873858-59029.

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In der vorliegenden Arbeit wurden Verbindungen untersucht, die reguläre oder verzerrte planar-quadratische Chalkogenschichten als ein wesentliches Strukturelement enthalten. Neben der Darstellung neuer Verbindungen und der Identifizierung des Phasenbestandes in den binären Zustandsdiagrammen Ln – Se lag das Hauptaugenmerk der Untersuchungen auf der Aufklärung der z. T. komplexen Überstrukturen und deren kristallchemischen Einordnung sowie auf den elektronischen Eigenschaften der Verbindungen. Methodisch kamen zur Strukturlösung und -beschreibung dabei sowohl Röntgen- und Elektronenbeugung, als auch hochauflösende Transmissionselektronenmikroskopie und Elektronenholographie zum Einsatz. Bei Strukturverfeinerungen der kommensurabel und inkommensurabel modulierten Strukturen wurde in vielen Fällen das Superraumkonzept angewandt, das eine einheitlichere Beschreibung verwandter Strukturen in höherdimensionalen Superraumgruppen ermöglicht. Im einzelnen wurden die Polyselenide PrSe2 und NdSe2 (beide kristallisieren im CeSe2-Typ) und SmSe1.9 (CeSe1.9-Typ) sowie die selenärmeren Verbindungen Ln8Se15 mit Ln = Y, Gd, Tb, Dy, Ho und Er (alle: Gd8Se15-Typ) hergestellt und erstmals strukturell charakterisiert. Diese Verbindungen kristallisieren als kommensurable Überstrukturen eines hochsymmetrischen Aristotyps, des ZrSSi-Typs. Die ebenfalls neu aufgefundenen Selenide Nd0.6Gd0.4Se1.85 und PrSe1.85 bilden dagegen inkommensurabel modulierte Strukturen aus und werden mit Hilfe des Superraumformalismus beschrieben. Die untersuchten Polyselenide weisen halbleitendes Verhalten auf und enthalten dreiwertige Lanthanoidmetalle. Die ebenfalls neu aufgefundenen Substanzklasse der Lanthanoidselenidditelluride LnSeTe2 (Ln = La, Ce, Pr, Nd, Sm) sind als ternäre Ordnungsvarianten des NdTe3-Typs zu beschreiben. Die Verbindungen LaSeTe2, CeSeTe2, PrSeTe2 und NdSeTe2 durchlaufen reversible, temperaturabhängige Phasentransformationen von einer nicht modulierten Hochtemperaturphase in eine inkommensurabel modulierte Tieftemperaturphase, die mit einem Metall-Halbmetall-Übergang korreliert.

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Warzycha, Karolina Verfasser], and Arno [Akademischer Betreuer] [Pfitzner. "Transition Metal Antimony (III) Oxidehalides. Synthesis, crystal structure and physical characteristics / Karolina Warzycha. Betreuer: Arno Pfitzner." Regensburg : Universitätsbibliothek Regensburg, 2010. http://d-nb.info/1022819666/34.

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Kolodiazhnyi, Taras Petric Anthony. "Semiconducting and dielectric properties of barium titanates, tantalates and niobates with perovskite structure /." *McMaster only, 2002.

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Vennström, Marie. "Crystal Chemistry of the Ti3Sn-D, Nb4MSi-D and Pd-Ni-P Systems." Doctoral thesis, Uppsala universitet, Institutionen för materialkemi, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3466.

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Future energy systems based on hydrogen as energy carrier require reliable ways for storing hydrogen gas in safe, clean and efficient ways. Metal hydrides absorb hydrogen gas reversibly, making them suitable for storage applications. Investigations of the crystal structures of these materials contribute to an understanding of the factors which can influence the absorption. Three systems, Ti3Sn-D, Nb4MSi-D (M=Co or Ni) and Pd-Ni-P, have been investigated in this thesis. Various solid state synthesis techniques have been used for sample preparation. The crystal structures have been studied using x-ray and neutron diffraction techniques. Three metal hydride phases were found in the Ti3Sn-D system upon hydrogenation. Deuterium occupies titanium octahedra and the applied deuterium pressure induces the phase transitions. The distances between the deuterium atoms increase from 2.47 Å in orthorhombic Ti3SnD0.80 to 4.17 Å in cubic Ti3SnD. The Nb4MSi-D system (M=Co or Ni) readily absorbs deuterium at room temperature and 90 kPa deuterium pressure to give a deuterium content of Nb4MSiD~2.5. Two interstitial voids, both coordinated by four niobium atoms arranged in a tetrahedral configuration, accommodate deuterium atoms. Two ternary phases and a solid solution of nickel in Pd3P have been synthesised and the crystal structures determined. PdNi2P is orthorhombic and crystallises in the MgCuAl2-type structure: an ordered derivative of the Re3B-type structure. Pd8Ni31P16 is a tetragonal high-temperature phase stable at 700°C with 110 atoms in the unit cell. Pd2.7Ni0.3P0.94 has the cementite-type structure with mixed occupancy of palladium and nickel at one of the two non-equivalent crystallographic metal positions.

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Lucas, Kaitlyn D. "Magnesium Sulfonyldibenzoates: Synthesis, Structure, Phase Transformation and Microscopic Studies." Youngstown State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1391780070.

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Hashiguchi, Ryota. "Studies on Polynuclear Metal Complexes and Low-Dimensional Mixed-Valence Halogen-Bridged Transition Metal Complexes Based on them." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225426.

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Otake, Ken-ichi. "Studies on the Dimensional-Extended Halogen-Bridged Mixed-Valence Transition-Metal Complexes: Neutral-Chains and Nanotubes." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/217132.

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Doert, Thomas. "Quadratische Netze, Fehlstellen und Modulationen Strukturchemie von Polyseleniden und Selenidditelluriden der Lanthanoidmetalle /." Doctoral thesis, [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=982363834.

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張碧玉 and Pik-yuk Christine Cheung. "Crystal structure analysis of imido, nitrido and oxo complexes of rhenium (V), osmium (VI) and ruthenium (III) and some complexes oftrinuclear gold (I)." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1991. http://hub.hku.hk/bib/B31210211.

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Krug, Claudio Kristoffer [Verfasser], and J. Michael [Akademischer Betreuer] Gottfried. "Structure and Reactivity of Aromatic Molecules on Metal Single-Crystal Surfaces and at Metal/Organic Interfaces / Claudio Kristoffer Krug ; Betreuer: J. Michael Gottfried." Marburg : Philipps-Universität Marburg, 2020. http://d-nb.info/121868593X/34.

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33

李鼎威 and Ting-wai Lee. "Self-assembly and crystal structure analysis of some first-row transition metal coordination polymers of 1,3-bis(4-pyridyl)propane." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31224660.

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Lee, Ting-wai. "Self-assembly and crystal structure analysis of some first-row transition metal coordination polymers of 1,3-bis(4-pyridyl)propane." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23242322.

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35

Cheung, Pik-yuk Christine. "Crystal structure analysis of imido, nitrido and oxo complexes of rhenium (V), osmium (VI) and ruthenium (III) and some complexes of trinuclear gold (I) /." [Hong Kong : University of Hong Kong], 1991. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13138327.

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36

George, Lyci. "Structural Characterization of Metal Hydrides for Energy Applications." FIU Digital Commons, 2010. http://digitalcommons.fiu.edu/etd/233.

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Hydrogen can be an unlimited source of clean energy for future because of its very high energy density compared to the conventional fuels like gasoline. An efficient and safer way of storing hydrogen is in metals and alloys as hydrides. Light metal hydrides, alanates and borohydrides have very good hydrogen storage capacity, but high operation temperatures hinder their application. Improvement of thermodynamic properties of these hydrides is important for their commercial use as a source of energy. Application of pressure on materials can have influence on their properties favoring hydrogen storage. Hydrogen desorption in many complex hydrides occurs above the transition temperature. Therefore, it is important to study the physical properties of the hydride compounds at ambient and high pressure and/or high temperature conditions, which can assist in the design of suitable storage materials with desired thermodynamic properties. The high pressure-temperature phase diagram, thermal expansion and compressibility have only been evaluated for a limited number of hydrides so far. This situation serves as a main motivation for studying such properties of a number of technologically important hydrides. Focus of this dissertation was on X-ray diffraction and Raman spectroscopy studies of Mg2FeH6, Ca(BH4)2, Mg(BH4)2, NaBH4, NaAlH4, LiAlH4, LiNH2BH3 and mixture of MgH2 with AlH3 or Si, at different conditions of pressure and temperature, to obtain their bulk modulus and thermal expansion coefficient. These data are potential source of information regarding inter-atomic forces and also serve as a basis for developing theoretical models. Some high pressure phases were identified for the complex hydrides in this study which may have better hydrogen storage properties than the ambient phase. The results showed that the highly compressible B-H or Al-H bonds and the associated bond disordering under pressure is responsible for phase transitions observed in brorohydrides or alanates. Complex hydrides exhibited very high compressibility suggesting possibility to destabilize them with pressure. With high capacity and favorable thermodynamics, complex hydrides are suitable for reversible storage. Further studies are required to overcome the kinetic barriers in complex hydrides by catalytic addition. A comparative study of the hydride properties with that of the constituting metal, and their inter relationships were carried out with many interesting features.

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37

Vennström, Marie. "Crystal Chemistry of the Ti₃Sn-D, Nb₄MSi-D and Pd-Ni-P Systems." Doctoral thesis, Uppsala University, Department of Materials Chemistry, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3466.

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Future energy systems based on hydrogen as energy carrier require reliable ways for storing hydrogen gas in safe, clean and efficient ways. Metal hydrides absorb hydrogen gas reversibly, making them suitable for storage applications. Investigations of the crystal structures of these materials contribute to an understanding of the factors which can influence the absorption.

Three systems, Ti₃Sn-D, Nb₄MSi-D (M=Co or Ni) and Pd-Ni-P, have been investigated in this thesis. Various solid state synthesis techniques have been used for sample preparation. The crystal structures have been studied using x-ray and neutron diffraction techniques.

Three metal hydride phases were found in the Ti₃Sn-D system upon hydrogenation. Deuterium occupies titanium octahedra and the applied deuterium pressure induces the phase transitions. The distances between the deuterium atoms increase from 2.47 Å in orthorhombic Ti₃SnD_0.80 to 4.17 Å in cubic Ti₃SnD.

The Nb₄MSi-D system (M=Co or Ni) readily absorbs deuterium at room temperature and 90 kPa deuterium pressure to give a deuterium content of Nb₄MSiD_~2.5. Two interstitial voids, both coordinated by four niobium atoms arranged in a tetrahedral configuration, accommodate deuterium atoms.

Two ternary phases and a solid solution of nickel in Pd₃P have been synthesised and the crystal structures determined. PdNi₂P is orthorhombic and crystallises in the MgCuAl₂-type structure: an ordered derivative of the Re₃B-type structure. Pd₈Ni₃₁P₁₆ is a tetragonal high-temperature phase stable at 700°C with 110 atoms in the unit cell. Pd_2.7Ni_0.3P_0.94 has the cementite-type structure with mixed occupancy of palladium and nickel at one of the two non-equivalent crystallographic metal positions.

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38

Czulucki, Andreas. "Struktur-/Eigenschafts-Beziehungen in ternären Übergangs- und Seltenerdmetall-Pniktid-Chalkogeniden." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-33354.

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Ziel dieser Arbeit war es, Beziehungen zwischen den kristallchemischen Eigenschaften und dem beobachteten anomalen Verhalten im spezifischen elektrischen Widerstand (nicht-magnetischer Kondo-Effekt) aufzuzeigen und zusammenhängend zu interpretieren. Verbindungen, an denen dieser Effekt beobachtet wurde, werden aus einem Übergangs-, oder Actinidmetall mit je einem Vertreter der 15. (Pniktogene) und 16. Gruppe (Chalkogene) des Periodensystems gebildet und kristallisieren im PbFCl-Strukturtyp. Da zu ternären Actinidmetall-Pniktid-Chalkogeniden (z.B. ThAsSe, UPS) nur sehr wenige chemische und kristallographische Informationen existieren, wurden in dieser Arbeit umfassende Untersuchungen zur Kristallchemie ternärer Phasen aus den Systemen M-Pn-Q (M = Zr, Hf, La-Ce; Pn = As, Sb; Q = Se, Te durchgeführt. Der Schwerpunkt lag dabei auf der strukturellen Lokalisierung der beobachteten Widerstandsanomalie und der Erarbeitung chemisch-physikalischer Eigenschaftsbeziehungen. Die Darstellung der untersuchten ternären Phasen in Form von Einkristallen gelang über exothermen Chemischen Transport mit Jod. Da die erhaltenen Kristalle bis zu mehreren Millimetern groß sind, konnten an ein und demselben Kristallindividuum sowohl die stoffliche Charakterisierung (EDXS, WDXS, ICP-OES, LA-ICP-MS, CIC) und die strukturelle Charakterisierung, als auch die Messung der physikalischen Eigenschaften erfolgen. Es konnte u.a. gezeigt werden, dass ZrAs1,4Se0,5 und HfAs1,7Se0,2 ein ähnlich ungewöhnliches Verhalten im temperaturabhängigen elektrischen Widerstand zeigen, welches bereits an Thorium-Arsenid-Seleniden und Uran-Phosphid-Sulfiden beobachtet wurde. Desweiteren gelang es den beobachteten Verlauf im elektrischen Widerstand, mit seinem Minium bei etwa T = 15 K, auf intrinsische strukturelle Merkmale in der anionischen Arsen-Teilstruktur zurückzuführen
The aim of this work was, to evaluate and interpret a relationship between the crystal-chemical properties and the observed unusual behavior in the electrical resistivity (non-magnetic Kondo-effect). Compounds, which show such an effect, are formed by a transition- or actinide-metal with both a group 15 element and a group 16 element of the periodic table. All these compounds crystallizing in the PbFCl type of structure. Because of less crystallographic and chemical information about actinide-metal-pnictide-chalcogenides (i.e. ThAsSe, UPS), intensive investigation were made concerning the crystal-chemistry of ternary phases of the systems M-Pn-Q (M = Zr, Hf, La-Ce; Pn = As, Sb; Q = Se, Te. Our studies were focused on the structurally localization of the observed anomaly in the electrical resistivity and the evaluation of chemical-physical relations of properties. The synthesis of the investigated ternary phases was realized by exothermically Chemical Transport with iodine as transport agent. The dimension of the synthesized crystals allowed a chemical (EDXS, WDXS, ICP-OES, LA-ICP-MS, CIC) and structurally characterization, as well as a determination of the physical properties on one large single crystal. It could be shown, that ZrAs1,4Se0,5 and HfAs1,7Se0,2 reveal a similar unusual behavior in the temperature dependent electrical resistivity, as it was observed in thorium-arsenide-selenides and uranium-phosphide-sulphides. In conclusion, the non-magnetic Kondo-effect, which was found in the low-temperature range (about 15 K), arises from structurally features of the anionic sublattice with arsenic

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39

Schumer, Benjamin N., Marcelo B. Andrade, Stanley H. Evans, and Robert T. Downs. "A new formula and crystal structure for nickelskutterudite, (Ni,Co,Fe)As-3, and occupancy of the icosahedral cation site in the skutterudite group." MINERALOGICAL SOC AMER, 2017. http://hdl.handle.net/10150/623060.

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We propose a new formula for the mineral nickelskutterudite, based on our observation that either (or both) Co or Fe3+ are essential structure constituents. The crystal structure of nickelskutterudite, (Ni,Co,Fe) As-3, cubic, Im (3) over bar, Z = 8: a = 8.2653(6) angstrom, V = 564.65(7) angstrom, has been refined to R-1 = 1.4% for 225 unique reflections I > 2 sigma(1) collected on a Bruker X8 four-circle diffractometer equipped with fine-focus, sealed tube MoKa radiation and an APEX-II CCD detector. This is the first report of the crystal structure of nickelskutterudite. Nickelskutterudite, a member of the skutterudite group of isostructural minerals, adopts a distorted perovskite structure with notably tilted octahedra and an unoccupied to partially occupied icosahedral metal site. In the structure of nickelskutterudite, there is one metal (B) site occupied by Ni, Co, or Fe in octahedral coordination with six As atoms. Procrystal electron density analysis shows each As anion is bonded to two cations and two As anions, resulting in a four-membered ring of bonded As with edges 2.547 and 2.475 angstrom. The extreme tilting of BAs6 octahedra is likely a consequence of the As-As bonding. The nickelskutterudite structure differs from the ideal perovskite structure (A(4)B(4)X(12)) in that As4 anion rings occupy three of the four icosahedral cages centered on the A sites. There are reported synthetic phases isomorphous with skutterudite with the other A site completely occupied by a cation (AB(4)X(12)). Electron microprobe analyses of nickelskutterudite gave an empirical chemical formula of (Ni0.62Co0.28Fe0.12)(Sigma 1.02)(AS(2.95)S(0.05))(Sigma 3.00) normalized to three anions. Pure NiAs3 nickelskutterudite, natural or synthesized, has not been reported. In nature, nickelskutterudite is always observed with significant Co and Fe, reportedly because all non-bonded valence electrons must be spin-paired. This suggests that nickelskutterudite must contain Co3+ and Fe2+, consistent with previous models since Ni4+ cannot spin-pair its seven non-bonded electrons, Co3+ and Fe2+, which can spin-pair all non-bonded electrons, are required to stabilize the structure. No anion deficiencies were found in the course of this study so, including the structurally necessary Co and Fe, the chemical formula of nickelskutterudite (currently given as NiAs3-x, by the IMA) should be considered (Ni,Co,Fe)As-3.

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Åkerstedt, Josefin. "Subvalent Cluster Compounds and Synthesis in Alternative Reaction Media." Doctoral thesis, KTH, Tillämpad fysikalisk kemi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-107218.

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With the aim of finding alternative reaction media for the synthesis of subvalent main group and transition metal cluster compounds, traditionally made through solid state reactions or in superacidic media, different alternative reaction media have been explored in this work. Room-temperature ionic liquids are amongst the more unconventional reaction media used. The syntheses performed have been aimed at both anionic and cationic cluster and the main tools used for characterization have been different X-ray diffraction and spectroscopic techniques. Selected ionic liquids have along with dichloromethane been shown to work as alternative reaction media for room temperature synthesis of the Bi5[GaCl4]3 salt. The salt containing the subvalent naked bismuth polycation Bi5 3+ was isolated from reduction reactions of BiCl3 in Ga/GaCl3-dichloromethane respectively Ga/GaCl3-ioinc liquid media. Three different classes of ionic liquids based on phosphonium-, imidazolium- and pyrrolidinium- salts have been used in synthesis. Homopolyatomic clusters from the lighter Group 15 element arsenic have also been studied. Solutions from the oxidative and reductive reaction routes of arsenic and AsCl3 in Lewis acidic toluene media were studied by EXAFS spectroscopy. The results were evaluated using molecular dynamics simulations of arsenic clusters. A discussion on how the calculated As4 cluster model relates to the experimental data resulted from this study. In terms of homopolyatomic anionic clusters the [K+(2,2,2-crypt)]2Ge9 2- compound containing the naked Ge9 2- anionic cluster has been isolated. The crystallographic investigation of [K+(2,2,2-crypt)]2Ge9 2- shows Zintl cluster anion Ge9 2- to be tricapped trigonal-prismatic with a symmetry very close to D3h. A chemical bonding analysis reveals two local minima of D3h symmetry and the cluster interaction scheme to be based on highly delocalised bonding. Ligand supported transition metal clusters from tungsten and palladium have also been prepared. Reduction of WCl6 in a reaction mixture of ionic liquid and co-solvent toluene resulted in tritungsten decachloride; W3Cl10(MeCN)3, being formed. Furthermore, palladium sandwich compounds; [Pd2(Ga2Cl7)(C7H8)2], [Pd2(GaCl4)(C9H12)2]∙C9H12 and [Pd2(Ga2Cl7)(C6H5Cl)2] have been prepared using GaCl3-arene reaction media.

QC 20121212

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41

Prescott, Hillary Anne. "The crystal structures and thermal behavior of hydrogen monofluorophosphates and basic monofluorophosphates with alkali metal and N-containing cations." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2001. http://dx.doi.org/10.18452/14706.

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In vorliegender Arbeit wurden Synthese, Kristallstruktur und thermisches Verhalten von sauren und basischen Monofluorophosphate untersucht. Es wurden Salze mit Alkalimetall- und N-haltigen Kationen dargestellt und kristallographisch charakterisiert. Die Strukturen dieser Verbindungen wurden dann mit denen der isoelektronischen Hydrogensulfate verglichen. Mit Hilfe des Kationenaustausches und der Gefriertrocknung konnte ein erfolgreicher Syntheseweg fuer diese Verbindungen entwickelt werden. Die Gefriertrocknung hinderte die Abspaltung von HF und Kondensation des Phosphats und ermöglichte die Isolierung der Rohprodukte. Auf diesem Weg gelang die Darstellung der reinen Verbindungen in höherer Ausbeute, so daß es möglich wurde, die Substanzen mit unterschiedlichen Methoden zu untersuchen. Hergestellt und kristallographisch untersucht wurden folgende Verbindungen: - Hydrogenmonofluorophosphate mit × Alkalimetallkationen: Na, K, Rb, Cs × N-haltigen Kationen: NH4, NMe4, NH2Et2, NHEt3, [C(NH2)3], {HOC[NH(CH3)]2}, [H2N(CH2CH2)NH2], - basische Monofluorophosphate: Na2PO3F·10H2O und [C(NH2)3]2PO3F - gemischte Salze: Cs3(NH4)2(HPO3F)3(PO3F)2 und Na5[NMe4](PO3F)3·18H2O. Die Kristallstrukturen zeigen eine Vielzahl an Strukturtypen, definiert durch die Verknüpfung der verzerrten HPO3F Tetraeder über kurze O-H···O Wasserstoffbrückenbindungen zu Ketten, Dimere oder Tetramere. Diese sind ihrerseits über längere N-H···O und Ow-H···O Wasserstoffbrückenbindungen verknüpft. Kompliziertere Strukturmotive sind in den Strukturen der basischen Monofluorophosphate und der gemischten Salze zu finden. Allgemein werden nur Wasserstoffbrückenbindungen des Typs N-H...O und O-H...O gefunden, dagegen werden keine N-H···F Bindungen in den Strukturen beobachtet. Auch ist mehrheitlich keine Isotypie zwischen sauren und basischen Monofluorophosphaten einerseits und den entsprechenden Sulfaten andererseits zu finden. Isotyp sind nur die Strukturen [NMe4]HPO3F·H2O mit [NMe4]HSO4·H2O und Na2PO3F·10H2O mit Na2SO4·10H2O. Interessanterweise wurden genau in einer dieser isotypen Strukturen, nämlich der des Na2PO3F×10H2O, als Ausnahme zwei O-H···F Bindungen gefunden. Die O···F Abstände liegen im Bereich der Abstände der Ow···O Bindungen in der Struktur. Eine Erklärung für das seltene Auftreten von H-Brücken mit Fluor als Akzeptor ist eine fast vollständige Valenz des Fluors durch seine Bindung zum Phosphor. Mehrere Strukturen widerspiegeln diese Tatsache mit der Orientierung der P-F Bindung. Die Bindung wird nach inerten Stellen, wo kein Metall- oder Wasserstoffatom in der Struktur vorhanden ist, ausgerichtet, um ein weiteres Binden des Fluors (Metallkoordination, Wasserstoffbrückenbindung) zu vermeiden. Weiterhin wurde das thermische Verhalten der Verbindungen NaHPO3F, NaHPO3F·2.5H2O, CsHPO3F und [NHEt3]HPO3F untersucht. Dies erfolgte mit dem Ziel, Information über mögliche Phasenübergänge und die unterschiedlichen Zersetzungstypen zu bekommen. Sowohl der Kation wie auch die Anwesenheit von Kristallwasser haben Einfluß auf den thermischen Abbau. Die Na-Verbindungen zeigen eine Zersetzung über mehrere Schritte, die zu unterschiedlichen Endprodukten führt (Na3P3O9 für NaHPO3F und (NaPO3)n für das Hydrat). Im Vergleich dazu zersetzt sich CsHPO3F nach dem Schmelzen direkt zum Endprodukt, ohne stabile Zwischenprodukte zu bilden. Ähnlich verläuft der thermische Abbau der [NHEt3] Verbindung, die sich allerdings mit einem Masseverlust von 92,27%, also ohne Bildung eines signifikanten Endproduktes, vollständig zersetzt. Während des thermischen Abbaus wurde die Freisetzung von HF und H2O bei allen Verbindungen beobachtet, die sich aber bezüglich der Zersetzungstemperatur und -menge zwischen den Substanzen unterscheiden. Es wurden keine Phasenübergänge erster Ordnung beobachtet. Dies war insbesondere für CsHPO3F überraschend, da das isoelektronische Hydrogensulfat mehrere Phasenübergänge aufweist [2]. Das Ausbleiben von Phasenübergängen allgemein und auch für CsHPO3F wird folgendermassen erklärt. Während das Sulfat Bindungsmöglichkeiten an allen vier Ecken des SO4-Tetraeders hat, besitzt der (H)PO3F-Tetraeder nur eine begrenzte Flexibilität wegen der Anwesenheit von Fluor an einer Ecke. Fluor bevorzugt eine "isolierte" Position am Phosphor. Anhand der vorliegenden Ergebnisse kann die Schlußfolgerung gezogen werden, daß Fluor auf Grund seiner niedrigeren Valenz im Vergleich zu Sauerstoff andere strukturelle und funktionelle Charakteristika aufweist. Die Valenzunterschiede zwischen Sauerstoff und Fluor haben einen starken Einfluß auf das Wasserstoffbrückenbindungssystem in den Kristallstrukturen der Hydrogenmonofluorophosphate und folglich auf die "Nicht-Isotypie" zu den Hydrogensulfaten.
In this thesis, the crystal structures and thermal behavior of hydrogen monofluorophosphates and basic monofluorophosphates with alkali metal and N-containing cations were studied. A comparison to the analogous hydrogen sulfates showed interesting structural variations and differences in thermal behavior. Synthesis of the studied monofluorophosphates involved cation exchange and freeze drying. Freeze drying enabled the isolation of raw products by avoiding the escape of HF and consequent phosphate condensation. This method of preparation led to the synthesis of the hydrogen monofluorophosphates with the following cations: - the alkali metals: Na+, K+, Rb+, and Cs+, - N-containing cations: NH4+, [NMe4]+, [NH2Et2]+, [NHEt3]+, [C(NH2)3]+, {HOC[NH(CH3)]2}+, and [H2N(CH2CH2)NH2]2+, and the basic monofluorophoshates, Na2PO3F·10H2O and [C(NH2)3]2PO3F. The following mixed salts were also obtained with partial cation exchange: - Cs3(NH4)2(HPO3F)3(PO3F)2 - Na5[NMe4](PO3F)3·18H2O. In the crystal structures, the HPO3F tetrahedra were hydrogen-bonded to chains, dimers, and tetramers in the structures of the hydrogen monofluorophosphates. Extensive hydrogen bonding in the basic monofluorophosphates due to high amounts of crystal water led to more complicated structural motifs. Limitations on the bonding of fluorine were observed in each of the structures, whether it be metal coordination or hydrogen bonding. The valency of fluorine is filled by its bond to phosphorus and thus, generally, the fluorine atom does not participate in additional bonds. This explains why, for the most part, the hydrogen monofluorophosphates are not isostructural with the hydrogen sulfates. Only three atoms of the tetrahedron instead of four atoms are available for hydrogen bonding, which influences the crystal structure. This was further confirmed by the comparison of the decahydrates, Na2PO3F×10H2O and Na2SO4×10H2O, which are consequently isostructural based on two O-H×××F bonds formed in Na2PO3F·10H2O. These were the only hydrogen bonds found that involved fluorine as an hydrogen acceptor or donor. The investigations on the thermal behavior of NaHPO3F, NaHPO3F·2.5H2O, CsHPO3F, and [NHEt3]HPO3F found no first-order phase transitions. Stepwise decompositions were observed for the sodium salts, which was attributed to the formation of stable intermediates identified with simulated experiments. The Cs and [NHEt3] compounds demonstrated a direct decomposition postmelting. In general, the release of H2O from the melt occured at lower temperatures, while HF escaped at higher temperatures. The temperatures, at which this initially occured, and the first maximum observed were dependent on the cation and the presence of crystal water. The immediate decomposition of CsHPO3F after melting differs from that of the hydrogen sulfate, CsHSO4, which undergoes several phase transitions before decompositon. This suggests that the sulfate has more structural flexibility on the basis of the four oxygen corners of the tetrahedra. In comparison, the monofluorophosphate is limited in its bonding mobility due to the presence of fluorine on one of the tetrahedral vertices. Therefore, phase transitions are not observed prior to decomposition. It was concluded that fluorine functions differently in the crystal structures on the basis of its lower valency. Thus, the difference in valency between fluorine and oxygen affects the hydrogen bonding of the hydrogen monofluorophosphates and thus pervents the expected isotypy of the isoelectronic hydrogen monofluorophosphates and hydrogen sulfates.

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42

Chioncel, Mariana F. "Cobalt thin films produced by conventional and photo-assisted metal-organic chemical vapour deposition." Thesis, Keele University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327638.

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43

Sturtz, Benjamin Walden. "Synthesis and Structural Chemistry of Diamagnetic Dimeric Metal Phthalocyanines." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1496922051865658.

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44

Kalska-Szostko, Beata. "Mössbauer spectroscopy on selectred magnetic compounds." Doctoral thesis, Uppsala University, Department of Physics, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-529.

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The applications of magnetic materials are related to their magnetic and crystal structure as well as electronic properties. In this thesis, mainly experimental methods have been focussed on novel materials and bulk materials. A selection of materials were studied by several techniques like Mössbauer spectroscopy, X-ray and neutron diffraction and magnetisation measurements.

New technology allow us to prepare artificial materials with unic magnetic properties. Magnetic multilayers are very interesting not only from phenomenological point of view but also as good applications materials. In this work will be shown some results from Fe/V and Fe/Co multilayer system

The (Fe_1-xMn_x)₃P system has been studied at both ends of the composition range. At the Fe-rich end, compounds exhibiting ferromagnetic ordering are formed, while at the Mn-rich end, an antiferromagnetic coupling was discovered. The experimental results are supported by theoretical calculations.

Rare-earth compounds with focus on Fe_0.65Er_0.2B_0.15 were studied by means of traditional Mössbauer spectroscopy, Monochromatic Circular Polarized Mössbauer Spectroscopy, X-ray diffraction and magnetic mesurements. This compound shows interesting behaviour of Fe magnetic moment at low and room temperature.

The first magnetic studies on rhombohedral Li₃Fe₂(PO₄)₃ at low temperature has also been made and an antiferromagnetic structure was revealed.

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45

Zhang, Shi-Yuan. "Homochiral Metal-Organic Materials: Design, Synthetic and Enantioseletive Separation." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5163.

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Owing to the growing demand for enantiopurity in biological and chemical processes, tremendous efforts have been devoted to the synthesis of homochiral metal-organic materials (MOMs) because of their potential applications in chiral separation and asymmetric catalysis. In this dissertation, the synthetic strategies for homochiral MOMs are discussed keeping the focus on their applications. Two distinct approaches have been taken to synthesize chiral structures with different topologies and accessible cavities. The chiral MOMs have been utilized in enantioselective separation of racemates. Chiral variants of the prototypal metal-organic framework MOF-5, δ-CMOF-5 and [lambda]-CMOF-5, have been synthesized by preparing MOF-5 in the presence of L-proline or D-proline, respectively. CMOF-5 crystallizes in chiral space group P213 instead of Fm-3m as exhibited by MOF-5. The phase purity of CMOF-5 was validated by single crystal and powder X-ray diffraction, IR spectroscopy, TGA, N2 adsorption, microanalysis and solid-state CD. CMOF-5 undergoes a reversible single crystal to single crystal phase change to MOF-5 when immersed in a variety of organic solvents although N-methyl-2-pyrolidone, NMP, does not induce loss of chirality. Indeed, MOF-5 undergoes chiral induction when immersed in NMP, affording racemic CMOF-5. A pair of homochiral network materials (CNMs), [Co2(S-man)2(bpy)3](NO3)2·guests (1S) and [Co2(R-man)2(bpy)3](NO3)2·guests (1R) based upon S-mendelic acid and R-mendelic acid were synthesized and characterized, respectively. The cationic networks contain 1D homochiral channels with the cross section of 8.0 Å × 8.0 Å. The chiral amphiphilic channel surfaces lined with hydrophilic nitrate anions and hydrophobic phenyl groups are capable for multiple interactions with guest species. Chiral resolution of 1-phenyl-1-propanol (PP) enantiomers was performed utilizing the homochiral porosity of 1S and 1R through different time period at different temperatures with/without additives. The mechanism for enantioselective separation of PP was fully investigated through single crystal structural analysis of guest exchanged 1S and 1R. Chiral resolution of PP revealed enhanced performance with additive, which can significantly improve the ee value from 32% to 60%.

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46

Junior, Sauli dos Santos. "Estudos estruturais em compostos de interesse farmacológicos contendo átomos pesados." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-06052008-134426/.

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A determinação de estruturas tridimensionais de quelatos com metais pesados e de alguns potencialmente úteis agentes quelantes, é uma ferramenta muito importante no estudo de complexos que poderão agir como antídotos na intoxicação por ingestão de metais pesados. Um conhecimento detalhado destes complexos é exigido para auxiliar na modelagem de estruturas moleculares e na determinação de procedimentos que sejam mais efetivos na neutralização dos processos, desenvolvidos por indivíduos com intoxicação crônica por metais pesados. Aqui serão reportados os resultados de um estudo sistemático de complexos [TlMe2L], onde L = 2-mercapto-3-piridina ácido carboxílico (I), 6-mercapto-3-piridinametoxicarboxilato (II), 2-mercapto-3-piridina-metoxicarboxilato (III), 6-mercapto-3-piridina-etoxicarboxilato (IV) e 2-mercapto-3-piridina-etoxicarboxilato (V). O estudo dos arranjos supramoleculares destes complexos mostra que, apesar das diferenças na simetria dos grupos espaciais e os substituintes nos ligantes, o empacotamento no cristal são similares. Os complexos formam polimeros infinitos em uma, duas e três dimensões, baseadas em interações TI - S, T1 - N e T1 - O e ligações de hidrogênio. Existem várias formas de correções dos dados de difração de raios X em monocristais. Durante o processamento das intensidades coletadas realizam-se várias correções, tais como de Lorentz, polarização, absorção e eventualmente correção por deterioração da amostra. A correção por absorção é fortemente recomendada para cristais que possuem fortes absorvedores em sua forma estrutural. Foram estudados os efeitos da absorção dos raios X em amostras cristalinas e uma comparação dos resultados obtidos ao aplicar os diferentes métodos de correções por absorção disponíveis. Constatou-se que após serem realizados diferentes formas de correção por absorção, houve diferenças significativas nas figuras de mérito, picos e vales de densidade de carga residual e parâmetros de deslocamentos anisotrópicos. Já nos ângulos e distâncias de ligações não foram observados mudanças significativas.
The determination of the three-dimensional structures of heavy-metal chelates and of some potentially useful chelating agents is a very important to01 in the study of complexes that may act as antidotes against poisoning by ingestion of heavy metals. A detailed knowledge of these complexes is expected to assist in the design of molecular structures and procedures that are more effective in counteracting the life threatening processes inevitably developed by individuals with chronic heavy-metal intoxication. Within this framework a series of dimethylthallium(III) complexes were studied. Here we present complexes of the type [TlMe2L], where L=2-mercapto-3- pyridine carboxylic acid(I), 6-mercapto-3-pyridine-methoxycarboxylate(II), 2-mercapto-3-pyridine-methoxycarboxylate(III), 6-mercapto-3-pyridineethoxycarboxylate(IV) and 2-mercapto-3-pyridine-ethoxycarboxylate(V). The study of the supramolecular arrangement of these complexes shows that, in spite of the differences in space group symmetry and substituents in the ligand, the crystals packing are remarkably similar. The complexes form infinite polymers in one, two and three dimensions, based upon TI-S, T1-0 e T1-N covalent bonds and intermolecular secondary interactions. The complexes also present strong hydrogen bond intermolecular interactions. There are many forms of corrections to the data collected in a single crystal X-ray diffration experiment. During the data reduction many corrections take place, such as: Lorentz, polarization, absorption and eventualy corrections for the deterioration of the sample. The absorption correction is strongly recommended for crystals with strong absorbers in its structural form. The effect of the absorption of the X rays has been studied in crystalline samples, as well as a comparison between the result obtained from the different available methods of absorption corrections. This work that showed different forms of absorption correction, made significant differences in the merit figures, peak and hole of residual charge density, as well as the anisotropic displacements parameters. Bonds distances and angles, on the other hand, did not change significantly.

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47

Serra, Maia Rui Filipe. "Relation between surface structural and chemical properties of platinum nanoparticles and their catalytic activity in the decomposition of hydrogen peroxide." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/85149.

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The disproportionation of H₂O₂ to H₂O and molecular O₂ catalyzed by platinum nanocatalysts is technologically very important in several energy conversion technologies, such as steam propellant thrust applications and hydrogen fuel cells. However, the mechanism of H₂O₂ decomposition on platinum has been unresolved for more than 100 years and the kinetics of this reaction were poorly understood. Our goal was to quantify the effect of reaction conditions and catalyst properties on the decomposition of H₂O₂ by platinum nanocatalysts and determine the mechanism and rate-limiting step of the reaction. To this end, we have characterized two commercial platinum nanocatalysts, known as platinum black and platinum nanopowder, and studied the effect of different reaction conditions on their rates of H₂O₂ decomposition. These samples have different particle size and surface chemisorbed oxygen abundance, which were varied further by pretreating both samples at variable conditions. The rate of H₂O₂ decomposition was studied systematically as a function of H₂O₂ concentration, pH, temperature, particle size and surface chemisorbed oxygen abundance. The mechanism of H₂O₂ decomposition on platinum proceeds via two cyclic oxidation-reduction steps. Step 1 is the rate limiting step of the reaction. Step 1: Pt + H₂O₂ → H₂O + Pt(O). Step 2: Pt(O) + H₂O₂ → Pt + O₂ + H₂O. Overall: 2 H₂O₂ → O₂ + 2 H₂O. The decomposition of H₂O₂ on platinum follows 1st order kinetics in terms of H₂O₂ concentration. The effect of pH is small, yet statistically significant. The rate constant of step 2 is 13 times higher than that of step 1. Incorporation of chemisorbed oxygen at the nanocatalyst surface resulted in higher initial rate of H₂O₂ decomposition because more sites initiate their cyclic process in the faster step of the reaction. Particle size does not affect the kinetics of the reaction. This new molecular-scale understanding of the decomposition of H₂O₂ by platinum is expected to help advance many energy technologies that depend on the rate of H₂O₂ decomposition on nanocatalysts of platinum and other metals.
Ph. D.

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48

Joshi, Sameehan Shrikant. "Non-Isothermal Laser Treatment of Fe-Si-B Metallic Glass." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1062821/.

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Metallic glasses possess attractive properties, such as high strength, good corrosion resistance, and superior soft magnetic performance. They also serve as precursors for synthesizing nanocrystalline materials. In addition, a new class of composites having crystalline phases embedded in amorphous matrix is evolving based on selective crystallization of metallic glasses. Therefore, crystallization of metallic glasses and its effects on properties has been a subject of interest. Previous investigations from our research group related to laser assisted crystallization of Fe-Si-B metallic glass (an excellent soft magnetic material by itself) showed a further improvement in soft magnetic performance. However, a fundamental understanding of crystallization and mechanical performance of laser treated metallic glass was essential from application point of view. In light of this, the current work employed an integrated experimental and computational approach to understand crystallization and its effects on tensile behavior of laser treated Fe-Si-B metallic glass. The time temperature cycles during laser treatments were predicted using a finite element thermal model. Structural changes in laser treated Fe-Si-B metallic glass including crystallization and phase evolution were investigated with the aid of X-ray diffraction, differential scanning calorimetry, resistivity measurements, and transmission electron microscopy. The mechanical behavior was evaluated by uniaxial tensile tests with an InstronTM universal testing machine. Fracture surfaces of the metallic glass were observed using scanning electron microscopy and site specific transmission electron microscopy. Fe-Si-B metallic glass samples treated with lower laser fluence (<0.49 J/mm2) underwent structural relaxation while higher laser flounces led to partial crystallization. The crystallization temperature experienced an upward shift due to rapid heating rates of the order of 104 K/s during laser treatments. The heating cycle was followed by termination of laser upon treatment attainment of peak temperature and rapid cooling of the similar order. Such dynamic effects resulted in premature arrest of the crystallite growth leading to formation of fine crystallites/grain (~32 nm) of α-(Fe,Si) as the major component and Fe2B as the minor component. The structural relaxation, crystallization fractions of 5.6–8.6 Vol% with α-(Fe,Si) as the main component, and crystallite/grain size of the order of 12 nm obtained in laser fluence range of 0.39-0.49 J/mm2 had minimal/no influence on tensile behavior of the laser treated Fe-Si-B metallic glass foils. An increase in laser fluence led to progressive increase in crystallization fractions with considerable amounts of Fe2B (2-6 Vol%) and increase in grain size to ~30 nm. Such a microstructural evolution severely reduced the strength of Fe-Si-B metallic glass. Moreover, there was a transition in fracture surface morphology of laser treated Fe-Si-B metallic glass from vein pattern to chevron pattern. Tensile loading lacked any marked influence on the crystallization behavior of as-cast and structurally relaxed laser-treated metallic glass foils. However, a significant crystallite/grain growth/coarsening of the order of two and half times was observed in the fractured region compared to the region around it for the laser-treated partially crystallized metallic glass foils. The simultaneous effects of stress generation and temperature rise during tensile loading were considered to play a key role in crystallite/grain growth/coarsening.

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49

Gillon, Amy Louise. "Structural and crystal engineering studies of metal complexes." Thesis, University of Bristol, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340299.

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50

Eriksson, Therese. "The Structural Basis for Magnetic Order in New Manganese Compounds." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5746.

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Dissertations / Theses on the topic 'Crystal structure of metals'

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