Reinvestigation of Crystal Structure and Non‐Stoichiometry in Copper Hydride, CuH_1–x (0 ≤ x ≤ 0.26)

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. Simulta-* Prof. Dr. H. Kohlmann

Structure and spectroscopy of CuH preparedviaborohydride reduction

“…This is in agreement with the most recent powder diffraction study (Auer & Kohlmann, 2014). In particular, the reported differences (Dasgupta & Mahanti, 2010) between the products from the Wü rtz and the borohydride routes; the colour and the relative stability are artefacts and are incorrect.…”

“…The combination of diffraction and vibrational spectroscopic studies clearly demonstrate that the CuH product resulting from synthesis by the borohydride route [equation (1)] is the same as that generated by the traditional synthesis based on Wü rtz's 1844 method. This is in agreement with the most recent powder diffraction study (Auer & Kohlmann, 2014). In particular, the reported differences (Dasgupta & Mahanti, 2010) between the products from the Wü rtz and the borohydride routes; the colour and the relative stability are artefacts and are incorrect.…”

“…This remains the most often used route to CuH (Warf & Feitknecht, 1950;Fitzsimons et al, 1995), although other routes have been developed including a sonochemical synthesis (Hasin & Wu, 2012), precipitation of the hydride from pyridine solutions of CuI and LiAlH 4 (Dilts & Shriver, 1968) ISSN 2052-5206 While the products from the Wü rtz and the pyridine methods have been extensively investigated (Korzhavyi et al, 2012;Soroka et al, 2013;Auer & Kohlmann, 2014;Bennett et al, 2015), that produced via equation (1) has been much less studied. This synthetic method results in an insoluble form of CuH, ('CuH/BH 4 '), that is coffee-coloured rather than the rust-red obtained from the Wü rtz synthesis.…”

“…However, CuO is a common product of the aerial decomposition of CuH and it exhibits a strong IR band at 537 cm À1 (Kliche & Popovic, 1990) and this is a more reasonable assignment. CuH/BH 4 was recently studied by Xray and neutron powder diffraction (Auer & Kohlmann, 2014). The aims of this paper are to use a combination of structural and spectroscopic methods to provide further insight into the nature of CuH formed via the borohydride route.…”

Vibrational spectroscopy with neutrons: Recent developments

“…One possibility is that this is present as CuH, copper (I) hydride. CuH has been known for almost 200 years [32], but has only recently been fully characterized [33][34][35][36]. One of the major puzzles was why CuH synthesized by aqueous methods (denoted as CuH/Würtz) differed so much from CuH synthesized from organic donor solvents (denoted as CuH/pyridine).…”