Materials Data on Sm2Ge2O7 by Materials Project

Abstract

Sm2Ge2O7 crystallizes in the tetragonal P4_12_12 space group. The structure is three-dimensional. Sm3+ is bonded to seven O2- atoms to form distorted SmO7 pentagonal bipyramids that share corners with five equivalent GeO4 tetrahedra, edges with five equivalent SmO7 pentagonal bipyramids, and an edgeedge with one GeO4 tetrahedra. There are a spread of Sm–O bond distances ranging from 2.29–2.62 Å. Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with five equivalent SmO7 pentagonal bipyramids, a cornercorner with one GeO4 tetrahedra, and an edgeedge with one SmO7 pentagonal bipyramid. There are a spread of Ge–O bond distances ranging from 1.75–1.81 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Sm3+ and one Ge4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three equivalent Sm3+ and one Ge4+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Sm3+ and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ge4+ atoms.