The pyrochlore-type molybdate Pr2Mo1.73Sc0.27O7

Abstract

Dipraseodymium molybdenum scandium heptaoxide, Pr2Mo1.73Sc0.27O7, crystallizes in the cubic pyrochlore-type structure. In the crystal, (Mo,Sc)O6 octahedra are linked together by common corners, forming a three-dimensional [(Mo,Sc)2O6] framework. The Pr atom and another O atom atom are located in the voids of this framework. The Mo and the Sc atom are distributed statistically over the same 16d crystallographic position, with site-occupancy factors of 0.867 (3) and 0.133 (3), respectively. The Pr3+ ions are surrounded by six O atoms from the MoO6 octahedra and by two other O atoms, forming a ditrigonal scalenohedron. All atoms lie on special positions. The Pr and the statistically distributed (Mo,Sc) sites are in the 16c and 16d positions with .-3m symmetry, and two O atoms are in 48f and 8a positions with 2.mm and -43m site symmetry, respectively.