Materials Data on Pr3GePO9 by Materials Project

Abstract

Pr3GePO9 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded to seven O2- atoms to form distorted PrO7 pentagonal bipyramids that share a cornercorner with one PO4 tetrahedra, corners with two equivalent GeO4 tetrahedra, an edgeedge with one PrO7 pentagonal bipyramid, and an edgeedge with one PO4 tetrahedra. There are a spread of Pr–O bond distances ranging from 2.37–2.62 Å. In the second Pr3+ site, Pr3+ is bonded in a 7-coordinate geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.42–3.01 Å. In the third Pr3+ site, Pr3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.45–2.65 Å. Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with two equivalent PrO7 pentagonal bipyramids. There are a spread of Ge–O bond distances ranging from 1.75–1.81 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one PrO7 pentagonal bipyramid and an edgeedge with one PrO7 pentagonal bipyramid. There is three shorter (1.55 Å) and one longer (1.57 Å) P–O bond length. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three Pr3+ and one Ge4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two Pr3+ and one P5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two Pr3+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Pr3+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to two Pr3+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Pr3+ and one Ge4+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to two Pr3+ and one Ge4+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to three Pr3+ and one Ge4+ atom. In the ninth O2- site, O2- is bonded to four Pr3+ atoms to form edge-sharing OPr4 tetrahedra.