The effect of cation coordination on the properties of oxygen vacancies in FeSbO4

Abstract

We present a theoretical study on the stability and electronic properties of oxygen vacancies in the mixed metal oxide FeSbO₄. Four different vacancy types were studied, differing by the coordination of the oxygen atoms removed: oxygen atoms coordinated to (a) three iron atoms, (b) two iron atoms and one antimony atom, (c) one iron atom and two antimony atoms and (d) three antimony atoms. The calculations show that both the stability and the electronic properties of the defective structures depend on the coordination. The higher the number of Sb atoms around the oxygen, the greater the energy to create the vacancy. The electrons remaining after the removal of a neutral oxygen atom localise close to Sb rather than to Fe, forming electron lone pairs which are orientated towards the oxygen vacancy site.