Synthesis and X-ray Diffraction Study of Radium Plumbate

Previously unknown mixed oxide RaPbO3 was prepared by thermal decomposition of a mixture of radium and lead carbonates. An X-ray diffraction study showed that radium plumbate crystallizes in the cubic perovskite structural type. The unit cell parameter (a = 4.303 angstrom) and crystallographic density (rho = 10.42 g cm(-3)) were determined. Formation of a new compound, RaPtO3-x, upon sintering of mixtures of radium and lead carbonates at 800 degrees C in a platinum crucible was detected. A similar barium compound can be formed upon calcination of barium compounds in platinum vessels in air.