Abstract
The new compound Ba2InCoO5 +
δ, which has a cubic perovskite structure (a
= 4.1587(3)
Å) at high temperatures, was prepared by heating mixtures of BaCO3, In2O3 and Co3O4 in air at 1150 °C for 20 h. Heat treatment of Ba2InCoO5 +
δ in air at 850 °C for 72 h revealed a phase transformation into a brownmillerite-type structure. To stabilize a cubic perovskite phase at moderate temperatures, the solid solutions Ba2In1 −
xCo1 +
xO5 +
δ, 0 ≤
x
≤ 0.7 and Ba2 −
xLaxCoInO5 +
δ, 0 ≤
x
≤ 0.8 were prepared.