Materials Data on NaGe4(PbO4)3 by Materials Project

Abstract

NaGe4(PbO4)3 crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.63 Å) and four longer (2.73 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with two equivalent PbO5 square pyramids and corners with six GeO4 tetrahedra. There are four shorter (2.32 Å) and two longer (3.01 Å) Na–O bond lengths. There are two inequivalent Pb+2.67+ sites. In the first Pb+2.67+ site, Pb+2.67+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Pb–O bond distances ranging from 2.32–2.73 Å. In the second Pb+2.67+ site, Pb+2.67+ is bonded to five O2- atoms to form distorted PbO5 square pyramids that share a cornercorner with one NaO6 octahedra, corners with five GeO4 tetrahedra, and an edgeedge with one GeO6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are a spread of Pb–O bond distances ranging from 2.28–2.64 Å. There are three inequivalent Ge+3.75+ sites. In the first Ge+3.75+ site, Ge+3.75+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one NaO6 octahedra, a cornercorner with one GeO6 octahedra, corners with two equivalent PbO5 square pyramids, and a cornercorner with one GeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–57°. There are a spread of Ge–O bond distances ranging from 1.74–1.79 Å. In the second Ge+3.75+ site, Ge+3.75+ is bonded to six O2- atoms to form GeO6 octahedra that share corners with three GeO4 tetrahedra, an edgeedge with one GeO6 octahedra, and an edgeedge with one PbO5 square pyramid. There are a spread of Ge–O bond distances ranging from 1.89–1.97 Å. In the third Ge+3.75+ site, Ge+3.75+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one NaO6 octahedra, a cornercorner with one GeO6 octahedra, a cornercorner with one PbO5 square pyramid, and corners with two equivalent GeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–80°. There is one shorter (1.74 Å) and three longer (1.79 Å) Ge–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Pb+2.67+ and two Ge+3.75+ atoms. In the second O2- site, O2- is bonded to one Na1+, two Pb+2.67+, and one Ge+3.75+ atom to form distorted ONaGePb2 trigonal pyramids that share corners with four ONaGePb2 trigonal pyramids and edges with three ONa2GePb trigonal pyramids. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Pb+2.67+ and one Ge+3.75+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Pb+2.67+ and two Ge+3.75+ atoms. In the fifth O2- site, O2- is bonded to two Na1+, one Pb+2.67+, and one Ge+3.75+ atom to form a mixture of distorted corner and edge-sharing ONa2GePb trigonal pyramids. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, one Pb+2.67+, and one Ge+3.75+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Pb+2.67+ and two equivalent Ge+3.75+ atoms. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two Ge+3.75+ atoms.