DOI: 10.17188/1291757
title: Materials Data on Ta5Pb11O26 by Materials Project

description: Ta5Pb11O26 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Ta+4.80+ sites. In the first Ta+4.80+ site, Ta+4.80+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent PbO6 octahedra, corners with four equivalent TaO6 octahedra, and edges with two equivalent PbO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 35–48°. There are two shorter (2.00 Å) and four longer (2.02 Å) Ta–O bond lengths. In the second Ta+4.80+ site, Ta+4.80+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent PbO6 octahedra, corners with four TaO6 octahedra, and edges with two equivalent PbO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 35–50°. There are two shorter (2.00 Å) and four longer (2.01 Å) Ta–O bond lengths. In the third Ta+4.80+ site, Ta+4.80+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra and corners with four PbO6 octahedra. The corner-sharing octahedra tilt angles range from 30–48°. There are a spread of Ta–O bond distances ranging from 1.99–2.01 Å. There are six inequivalent Pb+2.55+ sites. In the first Pb+2.55+ site, Pb+2.55+ is bonded to eight O2- atoms to form PbO8 hexagonal bipyramids that share edges with six TaO6 octahedra. There are two shorter (2.52 Å) and six longer (2.79 Å) Pb–O bond lengths. In the second Pb+2.55+ site, Pb+2.55+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Pb–O bond distances ranging from 2.33–3.03 Å. In the third Pb+2.55+ site, Pb+2.55+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Pb–O bond distances ranging from 2.30–3.06 Å. In the fourth Pb+2.55+ site, Pb+2.55+ is bonded in a hexagonal planar geometry to six O2- atoms. There are four shorter (2.62 Å) and two longer (2.93 Å) Pb–O bond lengths. In the fifth Pb+2.55+ site, Pb+2.55+ is bonded to six O2- atoms to form PbO6 octahedra that share corners with two equivalent PbO6 octahedra and corners with four equivalent TaO6 octahedra. The corner-sharing octahedra tilt angles range from 48–55°. There are two shorter (2.18 Å) and four longer (2.19 Å) Pb–O bond lengths. In the sixth Pb+2.55+ site, Pb+2.55+ is bonded to six O2- atoms to form PbO6 octahedra that share a cornercorner with one PbO6 octahedra and corners with five TaO6 octahedra. The corner-sharing octahedra tilt angles range from 44–55°. There are a spread of Pb–O bond distances ranging from 2.17–2.22 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ta+4.80+ and two Pb+2.55+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to one Ta+4.80+ and three Pb+2.55+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Ta+4.80+ and three Pb+2.55+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Ta+4.80+ and two Pb+2.55+ atoms. In the fifth O2- site, O2- is bonded to four Pb+2.55+ atoms to form a mixture of edge and corner-sharing OPb4 tetrahedra. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Ta+4.80+ and two Pb+2.55+ atoms. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to one Ta+4.80+ and three Pb+2.55+ atoms. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to one Ta+4.80+ and three Pb+2.55+ atoms. In the ninth O2- site, O2- is bonded to four Pb+2.55+ atoms to form a mixture of distorted edge and corner-sharing OPb4 tetrahedra.