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AbstractAbstract
[en] Solid-state metal hydrides display hydrogen densities close to that of liquid hydrogen and thus provide a safe and efficient way of storing hydrogen. As a result of recent neutron and synchrotron diffraction work some novel metal hydrides have been characterized that shed new light on the nature of metal-hydrogen interactions. While hydrogen appears as an anion surrounded by a large inventory of cation configurations in ionic hydrides such as Ca4Mg3H14, Ca19Mg8H54, Eu2MgD6, Eu6Mg7D26 and Eu2Mg3D10, it acts as a terminal ligand in covalently bonded hydride complexes based on p-elements such as [BH4]- and d-elements such as [IrH5]4- and [IrH4]5- in the complex hydrides LiBH4 and Mg6Ir2H11, respectively. Surprisingly, hydride complexes and hydride anions can also be discerned in typically metallic (interstitial) hydrides such as NdMgNi4H4 (= Nd3+Mg+2.[Ni4H4]5-) and LaMg2NiD7 (= La3+Mg+22.[NiH4]4-.3H-). Some hydrides also reveal other interesting features such as a hydrogenation induced Ce4+→Ce3+ valence change in CeMn1.8Al0.2H4.4 at room temperature that is accompanied by a Mn/Al metal atom exchange over distances of ∝2.6 A, and a hydrogen induced metal-to-nonmetal transition near ambient conditions that leads from the metallic compound Mg3Ir to the red colored hydride Mg6Ir2H11. In this article recent work and some methodological aspects are highlighted. (orig.)
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Journal Article
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ALKALI METAL COMPOUNDS, ALKALINE EARTH METAL COMPOUNDS, ALUMINIUM COMPOUNDS, BARIUM COMPOUNDS, BORON COMPOUNDS, CALCIUM COMPOUNDS, CERIUM COMPOUNDS, COHERENT SCATTERING, DEUTERIUM COMPOUNDS, DIFFRACTION, EUROPIUM COMPOUNDS, HYDRIDES, HYDROGEN COMPOUNDS, IRIDIUM COMPOUNDS, LANTHANUM COMPOUNDS, LITHIUM COMPOUNDS, MAGNESIUM COMPOUNDS, MANGANESE COMPOUNDS, NEODYMIUM COMPOUNDS, NICKEL COMPOUNDS, RARE EARTH COMPOUNDS, REFRACTORY METAL COMPOUNDS, SCATTERING, TRANSITION ELEMENT COMPOUNDS
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AbstractAbstract
[en] The partial loss of the cohesive metal-metal bonding in interstitial solid solutions of hydrogen in transition metals is compensated by Coulomb interactions. The hydrogen atoms occupy octahedral interstices at high electronegativity of the metal (PdH, NiH, β-VH). Otherwise tetrahedral sites are preferred by crystal field energy (delta-VH, β-TaH, NbH2, etc.). The metal lattice can get distorted by the repulsion of neighbouring atoms, which can be shown by Madelung calculations on β, γ, zeta-NbH and NbH2
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Furrer, A. (ed.); p. 239-242; 1977; p. 239-242; Plenum Press; New York; 2. international conference on the crystal field effects in metals and alloys; Zurich, Switzerland; 1 Sep 1976
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Book
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Conference
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CHEMICAL REACTIONS, CHROMIUM COMPOUNDS, CRYSTAL DEFECTS, CRYSTAL STRUCTURE, DISPERSIONS, ELEMENTS, HAFNIUM COMPOUNDS, HOMOGENEOUS MIXTURES, HYDRIDES, HYDROGEN COMPOUNDS, MIXTURES, NICKEL COMPOUNDS, NIOBIUM COMPOUNDS, PALLADIUM COMPOUNDS, POINT DEFECTS, SOLUTIONS, TANTALUM COMPOUNDS, TITANIUM COMPOUNDS, TRANSITION ELEMENT COMPOUNDS, VANADIUM COMPOUNDS, ZIRCONIUM COMPOUNDS
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AbstractAbstract
No abstract available
Original Title
hydrides of K, Ba, Nb, Ta, Y, Pr, Nd, Sm, Eu, Gd, Tb, Tm, Lu
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Journal Article
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Collection of Czechoslovak Chemical Communications; v. 38(8); p. 2320-2326
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BARIUM HYDRIDES, CHEMICAL REACTION KINETICS, DEUTERIUM, EUROPIUM HYDRIDES, GADOLINIUM HYDRIDES, HIGH TEMPERATURE, ISOTOPIC EXCHANGE, LUTETIUM HYDRIDES, NEODYMIUM HYDRIDES, NIOBIUM HYDRIDES, POTASSIUM HYDRIDES, PRASEODYMIUM HYDRIDES, SAMARIUM HYDRIDES, STABILITY, TANTALUM HYDRIDES, TEMPERATURE DEPENDENCE, TERBIUM HYDRIDES, THULIUM HYDRIDES, YTTRIUM HYDRIDES
ALKALI METAL COMPOUNDS, ALKALINE EARTH METAL COMPOUNDS, BARIUM COMPOUNDS, EUROPIUM COMPOUNDS, GADOLINIUM COMPOUNDS, HYDRIDES, HYDROGEN COMPOUNDS, HYDROGEN ISOTOPES, ISOTOPES, KINETICS, LIGHT NUCLEI, LUTETIUM COMPOUNDS, NEODYMIUM COMPOUNDS, NIOBIUM COMPOUNDS, NUCLEI, ODD-ODD NUCLEI, POTASSIUM COMPOUNDS, PRASEODYMIUM COMPOUNDS, RARE EARTH COMPOUNDS, REACTION KINETICS, SAMARIUM COMPOUNDS, STABLE ISOTOPES, TANTALUM COMPOUNDS, TERBIUM COMPOUNDS, THULIUM COMPOUNDS, TRANSITION ELEMENT COMPOUNDS, YTTRIUM COMPOUNDS
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AbstractAbstract
[en] Photoelectron spectroscopy studies of hydrogen-bearing metals and alloys have provided fundamental information concerning the electronic interactions of hydrides. Studies of surface oxidation of several hydrogen storage materials (the LaNi5-family) evaluated the role of surface oxidation on hydrogen uptake. Collaborative band theory studies were undertaken to support experimental studies of the metal-semiconductor transition in LaH2-LaH3 and of the refractory metal mono- and submonohydrides
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Sep 1982; 68 p; Available from NTIS, PC A04/MF A01 as DE83001373
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Report
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Weaver, J.H.; Peterson, D.T.; Peterman, D.J.
Ames Lab., IA (USA); Wisconsin Univ., Stoughton (USA). Synchrotron Radiation Center1980
Ames Lab., IA (USA); Wisconsin Univ., Stoughton (USA). Synchrotron Radiation Center1980
AbstractAbstract
[en] The electronic structures of representative metal hydrides have been examined through photoelectron and optical spectroscopies. The results of those studies ae compared with predictions of the one-electron band model for the various metal-hydrogen systems. Generally excellent agreement is found. The discussion emphasizes Nb4H3 and the dihydrides of Sc, Y, Nd, Gd, Tb, Er, Lu, Hf, and Th
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1980; 23 p; International symposium on the properties and applications of metal hydrides; Colorado Springs, CO, USA; 7 - 11 Apr 1980; CONF-800402--1; Available from NTIS., PC A02/MF A01
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Report
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Conference
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ACTINIDE COMPOUNDS, ELEMENTS, ERBIUM COMPOUNDS, GADOLINIUM COMPOUNDS, HAFNIUM COMPOUNDS, HYDRIDES, HYDROGEN COMPOUNDS, LUTETIUM COMPOUNDS, NEODYMIUM COMPOUNDS, NIOBIUM COMPOUNDS, NONMETALS, PHYSICAL PROPERTIES, RARE EARTH COMPOUNDS, SCANDIUM COMPOUNDS, TERBIUM COMPOUNDS, THORIUM COMPOUNDS, TRANSITION ELEMENT COMPOUNDS
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Weaver, J.H.; Peterman, D.J.; Peterson, D.T.
Electronic structure and properties of hydrogen in metals1983
Electronic structure and properties of hydrogen in metals1983
AbstractAbstract
[en] This chapter discusses metal-hydrogen electronic interactions in bulk hydrides by reviewing recent theoretical and experimental results for typical monohydrides (VH, NbH, and TaH), dihydrides (LaH2, PrH2, and NdH2), and trihydrides (LaH3). It attempts to highlight the basic physics behind the metal-hydrogen interaction in a variety of hydrides and compares experimental results with theoretical band structures and densities of states and finds generally good agreement, with exceptions noted. The chapter concludes that with the understanding of these relatively simple hydrides, it should be possible to examine the role of the electronic structure in the more complicated systems such as LaNi5H /SUB 6.7/
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Jena, P.; Satterthwaite, C.B; p. 207-222; 1983; p. 207-222; Plenum Press; New York, NY (USA); International symposium on the electronic structure and properties of hydrogen in metals; Richmond, VA (USA); 4-6 Mar 1982
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Book
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AbstractAbstract
[en] Ab initio molecular electronic structure theory has been applied to the family of transition metal tetrahydrides TiH4 through NiH4. For the TiH4 molecule a wide range of contracted Gaussian basis sets has been tested at the self-consistent-field (SCF) level of theory. The largest basis, labeled M(14s 11p 6d/10s 8p 3d), H(5s 1p/3s 1p), was used for all members of the series and should yield wave functions approaching true Hartree-Fock quality. Predicted SCF dissociation energies (relative to M+4H) and M--H bond distances are TiH4 132 kcal, 1.70 A; VH4 86 kcal, 1.64 A; CrH4 65 kcal, 1.59 A; MnH4 -- 36 kcal, 1.58 A; FeH4 0 kcal, 1.58 A; CoH4 27 kcal, 1.61 A; and NiH4 18 kcal, 1.75 A. It should be noted immediately that each of these SCF dissociation energies will be increased by electron correlation effects by perhaps as much as 90 kcal. For all of these molecules except TiH4 excited states have also been studied. One of the most interesting trends seen for these excited states is the shortening of the M--H bond as electrons are transferred from the antibonding 4t2 orbital to the nonbonding 1e orbitals
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Journal Article
Journal
Journal of Chemical Physics; ISSN 0021-9606;
; v. 71(2); p. 705-712

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AbstractAbstract
No abstract available
Source
International symposium on atomic, molecular, and solid-state theory and quantum biology; Sanibel Island, Fla; 18 Jan 1971
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Journal Article
Journal
Int. J. Quant. Chem., Symp; No. 5 p. 459-470
Country of publication
ERBIUM COMPOUNDS, BAND THEORY, CHROMIUM COMPOUNDS, ELECTRONIC STRUCTURE, ERBIUM HYDRIDES, HYDRIDES, MOLYBDENUM COMPOUNDS, NIOBIUM HYDRIDES, PALLADIUM HYDRIDES, PRASEODYMIUM HYDRIDES, SCANDIUM HYDRIDES, TANTALUM HYDRIDES, TITANIUM HYDRIDES, TUNGSTEN COMPOUNDS, VANADIUM HYDRIDES, YTTRIUM COMPOUNDS, YTTRIUM HYDRIDES
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AbstractAbstract
[en] Using a high pressure technique and the strong donating nature of H"-, a new series of tetragonal La_2Fe_2Se_2O_3-type layered mixed-anion arsenides, Ln_2M_2As_2H_x, was synthesized (Ln=La or Sm, M=Ti, V, Cr, or Mn; x∼3). In these compounds, an unusual M_2H square net, which has anti CuO_2 square net structures accompanying two As"3"- ions, is sandwiched by (LaH)_2 fluorite layers. Notably, strong metal-metal bonding with a distance of 2.80 Aa was confirmed in La_2Ti_2As_2H_2_._3, which has metallic properties. In fact, these compounds are situated near the boundary between salt-like ionic hydrides and transition-metal hydrides with metallic characters. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
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Available from: http://dx.doi.org/10.1002/anie.201409023; With 5 figs., 30 refs.
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AbstractAbstract
[en] A particulate mixture of ceramic powder, boron and a hydride of a metal selected from the group consisting of hafnium, niobium, tantalum, titanium, vanadium, zirconium and mixtures thereof is hot pressed decomposing the hydride and reacting the resulting metal with boron producing a polycrystalline microcomposite comprised of a continuous phase of the boride of the metal which encapsulates at least about 20% by volume of the ceramic particles and which either encapsulates or is intermixed with the balance of said ceramic particles
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23 Apr 1985; v p; US PATENT DOCUMENT 4,512,946/A/; U.S. Commissioner of Patents, Washington, D.C. 20231, USA, $.50; PAT-APPL-529784.
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Patent
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