Crystal structure of CsCrAs2O7, a new member of the diarsenate family

Abstract

Caesium chromium(III) diarsenate(V), CsCrAs2O7, was prepared by solid-state reactions. The title structure consists of isolated CrO6octahedra and As2O7diarsenate groups, sharing corners to build up a three-dimensional [CrAs2O7]−anionic framework. In this framework, channels extending parallel to [001] are present in which the ten-coordinate Cs+ions reside. CsCrAs2O7is isotypic with the monoclinicAIMIIIX2O7(AI= alkali metal;MIII= Al, Cr, Fe;X= As, P) type I family of compounds crystallizing in the space groupP21/c.