Structure Cristalline de Pb3MnT015

International audiencePb3Mn7O15 is orthorhombic, space group Cmc21, with a 17.28(1), b 19.98(1), and c 13.55(1) Å; d.(calculated) = 7.09 and d.(observed) = 7.03 for Z = 8. The structure was refined to R = 0.047. The structure consists of a succession of layers of octahedra perpendicular to the c-axis containing randomly distributed MnIII and MnIV atoms. The Pb atoms constitute hexagonal close packing with O. The electrostatic repulsion due to the lone pairs causes half of them to have 4-fold coordination analogous to that observed in the massicot variety of PbO and the others 6-fold coordination never before observe