Materials Data on Nb4Pb3O13 by Materials Project

Abstract

Pb3Nb4O13 crystallizes in the orthorhombic Pmma space group. The structure is three-dimensional. there are three inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six NbO6 octahedra, edges with two equivalent PbO8 hexagonal bipyramids, and edges with two equivalent PbO7 hexagonal pyramids. The corner-sharing octahedra tilt angles range from 31–45°. There are a spread of Nb–O bond distances ranging from 1.95–2.06 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six NbO6 octahedra, edges with two equivalent PbO8 hexagonal bipyramids, and edges with four equivalent PbO7 hexagonal pyramids. The corner-sharing octahedra tilt angles range from 40–41°. All Nb–O bond lengths are 2.02 Å. In the third Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six NbO6 octahedra and edges with four equivalent PbO7 hexagonal pyramids. The corner-sharing octahedra tilt angles range from 39–40°. There are four shorter (2.01 Å) and two longer (2.02 Å) Nb–O bond lengths. There are two inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded to seven O2- atoms to form distorted PbO7 hexagonal pyramids that share a cornercorner with one PbO7 hexagonal pyramid, edges with two equivalent PbO8 hexagonal bipyramids, an edgeedge with one PbO7 hexagonal pyramid, and edges with six NbO6 octahedra. There are a spread of Pb–O bond distances ranging from 2.23–2.83 Å. In the second Pb2+ site, Pb2+ is bonded to eight O2- atoms to form PbO8 hexagonal bipyramids that share edges with two equivalent PbO8 hexagonal bipyramids, edges with four equivalent PbO7 hexagonal pyramids, and edges with six NbO6 octahedra. There are a spread of Pb–O bond distances ranging from 2.50–2.73 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Nb5+ and one Pb2+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Nb5+ and two equivalent Pb2+ atoms. In the third O2- site, O2- is bonded to four Pb2+ atoms to form corner-sharing OPb4 tetrahedra. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Nb5+ and two equivalent Pb2+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two Nb5+ and two Pb2+ atoms. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Nb5+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Nb5+ and two equivalent Pb2+ atoms.