The invention relates to an oxide material of general formula (I) A.sub.2-x-yA'.sub.XA''.sub.yM.sub.1-z M'.sub.Z0.sub.4+.delta., wherein A and A' are independently a metal cation of a group formed by lanthanides and/or alkalis and/or alkaline earths, A'' is a cationic gap, i.e. a cation vacancy A and/or A', M and M' are independently a metal of a group formed by transition metals such as 0