Synthesis and solid state studies on Mb<inf>2</inf>Sb<inf>2</inf>O<inf>7</inf> and (Mn<inf>1-x</inf>Cd<inf>x</inf>)<inf>2</inf>Sb<inf>2</inf>O<inf>7</inf> pyrochlores

Pyrochlore oxides of the type Mn2Sb2O7 and (Mn1-xCdx)2Sb2O7 have been synthesized by high-temperature solid state reactions and characterized by X-ray diffraction and chemical analysis. X-Ray diffraction studies showed that the compound Mn2Sb2O7 has a rhombohedrally distorted pyrochlore structure. In the solid solutions (Mn1-xCdx)2Sb2O7, the phases with x ≥ 0.6 are cubic. Magnetic and 121Sb Mössbauer studies indicate that all the Mn and Sb are present in the +2 and +5 state occupying A and B sites, respectively, in the pyrochlore structure. Electrical measurements indicate that the compounds are insulators or semiconductors exhibiting p-type behavior. The stoichiometry and probable cause of the rhombohedral distortion in Mn2Sb2O7 and solid solutions are discussed. © 1984.