Gyepesová D, Langer V. Ca10(Cr(V)O4)6(Cr(VI)O4), a disordered mixed-valence chromium compound exhibiting inversion twinning.
Acta Crystallogr C 2013;
69:111-3. [PMID:
23377673 DOI:
10.1107/s0108270113000723]
[Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 01/08/2013] [Indexed: 11/10/2022] Open
Abstract
The structure analysis of so-called 9CaO·4CrO(3)·Cr(2)O(3) proved it to be the title compound, decacalcium hexakis[chromate(V)] chromate(VI), with the simultaneous presence of unusual chromium oxidation states. The structure determination was carried out on a crystal that had inversion twinning. The Cr(VI)O(4) tetrahedron is situated on a threefold axis and is disordered over two possible orientations that share three O atoms, while the Cr(V)O(4) tetrahedra are in general positions and are ordered. The charge is balanced by Ca(2+) cations, one of which is located on a threefold axis. The Ca(2+) ions are coordinated by six, seven or eight O atoms. The compound is a significant phase in the CaO-CrO(x) system and its formation reduces the refractoriness of calcium-rich compositions in an oxidizing atmosphere.
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