A structural comparison of the two polymorphs of Sr2Co2O5 by cobalt K-edge extended X-ray absorption fine structure spectroscopy

Abstract

The high- and low-temperature forms of Sr₂Co₂O₅ have been studied by EXAFS spectroscopy. Evidence is presented to support the belief that the high-temperature phase is isostructural with Sr₂Fe₂O₅. Furthermore, the observation of a Co–Co distance of 2.46 Å in the low-temperature form is the first direct evidence for the existence of face-sharing CoO₆ octahedra in that phase.