NEW ORDERED PEROVSKITES CONTAINING BISMUTH .5. [BALAMBIO(6) (M=MG, CA, SR)]

New Bi (V) containing perovskites oxides of the type, BaLaMBiO(6) (M = Mg, Ca, Sr) have been synthesized under high oxygen pressure conditio ns using the thermal decomposition of peroxides in a tetrahedral anvil apparatus. These compounds have been characterized by X-ray powder di ffraction and iodometric titration. All the BaLaMBiO(6) (M = Mg, Ca, S r) compounds show 1:1 type ordering of cations at the octahedral sites of the perovskite structure. In the case of magnesium and calcium con taining perovskites, comparison of the observed and the calculated X-r ay powder diffraction intensities show that the A sites are occupied b y barium and lanthanum in a disordered manner, and the octahedral site s are occupied by an ordered arrangement of bismuth and magnesium or b ismuth and calcium. This in contrast to strontium containing phase, wh ere the A sites are found to be occupied by barium and strontium in a disordered arrangement and the octahedral sites are occupied by lantha num and bismuth. The oxygen content, hence the oxidation state of Bi, in the samples depends on the synthetic conditions employed. The elect rical properties of the synthesized materials are discussed briefly.