Lithium cobalt(II) pyrophosphate, Li(1.86)CoP(2)O(7), from synchrotron X-ray powder data

Acta Crystallogr Sect E Struct Rep Online. 2011 Oct 1;67(Pt 10):i58-i59. doi: 10.1107/S1600536811038451. Epub 2011 Sep 30.

Abstract

Structure refinement of high-resolution X-ray powder diffraction data of the title compound gave the composition Li(1.865)CoP(2)O(7), which is also verified by the ICP measurement. Two Co sites exist in the structure: one is a CoO(5) square pyramid and the other is a CoO(6) octa-hedron. They share edges and are further inter-connected through P(2)O(7) groups, forming a three-dimensional framework, which exhibits different kinds of inter-secting tunnels containing Li cations and could be of great inter-est in Li ion battery chemistry. The structure also exhibits cation disorder with 13.5% Co residing at the lithium (Li1) site. Co seems to have an average oxidation state of 2.135, as obtained from the strutural stochiometry that closely supports the magnetic susceptibility findings.