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Reinvestigation of Crystal Structure and Non‐Stoichiometry in Copper Hydride, CuH 1– x (0 ≤ x ≤ 0.26)
Author(s) -
Auer Henry,
Kohlmann Holger
Publication year - 2014
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201400236
Subject(s) - copper , stoichiometry , chemistry , hydride , neutron diffraction , crystallography , hydrogen , deuterium , aqueous solution , inorganic chemistry , crystal structure , analytical chemistry (journal) , physics , organic chemistry , chromatography , quantum mechanics
Abstract Copper hydride and deuteride were reinvestigated by X‐ray and neutron powder diffraction, revealing a pronounced phase width with respect to the hydrogen (deuterium) content. Synthesis from aqueous copper(II) sulfate with hypophosphoric acid solutions yields samples with a broad distribution of compositions and variations of up to 6.5 % in unit cell volume. The result is a metrical distortion with ( hkl ) dependent asymmetry and broadening of powder diffraction reflections. Patterns of such samples were described using a model with five copper hydride (deuteride) phases with different lattice parameters. A method for developing and refining reasonable multiphase models despite high correlation of parameters is described. Simultaneous refinement on X‐ray and neutron powder diffraction on a deuteride sample suggests a statistical occupation of deuterium on less than half of the tetrahedral voids of a hexagonal close packing of copper atoms [ P 6 3 / mmc , a = 2.9024(5) Å, c = 4.632(2) Å, Cu in 2c, D in 4f with z = 0.6497(8), deuterium occupation 0.368(6)]. The reaction of aqueous copper(II) chloride with sodium boronate solutions yields copper hydride with a stoichiometric composition [ P 6 3 / mmc , a = 2.8777(3) Å, c = 4.570(1) Å, Cu in 2c, H in 4f with z = 0.640(1), hydrogen occupation 1/2]. The structures are isotypic to ScD 0.33 and reveal a surprising analogy to lanthanide hydrides.