Crystal structure of the ordered perovskite: BaBi0.5Sb0.5O3

The structure of BaBi0.5Sb0.5O3 is determined by single crystal X-ray diffraction. It is an ordered perovskite, having rhombohedral symmetry, space group R 3̄m (No. 166), with lattice parameters a = 6.043(1) Å and α = 60.05(2) °. The final agreement factor R based on F2 for 6420 reflections was 0.052. An important structural feature of BaBi0.5Sb0.5O3 is the displacements of oxygen atoms from their ideal positions within the pseudo-cubic [110]p planes, creating an alternative arrangement of (larger) BiO6 and (smaller) SbO6 octahedra. Therefore, the valence states of bismuth and antimony can be readily assigned as Bi(III) and Sb(V).