A quarter of a century after its synthesis and with >200 papers based on its use, `Co(CO3)0.5(OH)·0.11H2O' proves to be Co6(CO3)2(OH)8·H2O from synchrotron powder diffraction data

Prateek Bhojane; Armel Le Bail; Parasharam M Shirage

doi:10.1107/S2053229618017734

A quarter of a century after its synthesis and with >200 papers based on its use, `Co(CO₃)_0.5(OH)·0.11H₂O' proves to be Co₆(CO₃)₂(OH)₈·H₂O from synchrotron powder diffraction data

Acta Crystallogr C Struct Chem. 2019 Jan 1;75(Pt 1):61-64. doi: 10.1107/S2053229618017734. Epub 2019 Jan 1.

Authors

Prateek Bhojane¹, Armel Le Bail², Parasharam M Shirage¹

Affiliations

¹ Discipline of Metallurgy Engineering and Materials Science, Indian Institute of Technology Indore, Khandwa Road, Simrol, Indore 453 552, India.
² Université du Maine, Institut des Molécules et des Matériaux du Mans, CNRS UMR 6283, Av. Olivier Messiaen, 72085 Le Mans, France.

PMID: 30601132
DOI: 10.1107/S2053229618017734

Abstract

The successful attempt to solve the crystal structure of Co(CO₃)_0.5(OH)·0.11H₂O (denoted CCH), based on synchrotron powder diffraction data, leads to a drastic revision of the chemical formula to Co₆(CO₃)₂(OH)₈·H₂O [hexacobalt(II) bis(carbonate) octahydroxide monohydrate] and to a hexagonal cell instead of the orthorhombic cell suggested previously [Porta et al. (1992). J. Chem. Soc. Faraday Trans. 88, 311-319]. This results in a new structure-type related to malachite involving infinite chains of [CoO₆] octahedra sharing edges along a short c axis, delimiting tunnels having a three-branched star section. All reports discussing cobalt hydroxycarbonates (CCH) without any structural knowledge and especially its topotactic decomposition into Co₃O₄ have, as a result, to be reconsidered.

Keywords: ab initio; cobalt(II) carbonate hydroxide hydrate; malachite; powder diffraction; synchrotron.

Publication types

Research Support, Non-U.S. Gov't

Abstract

Publication types

Grants and funding