Materials Data on KNb5Pb2O15 by Materials Project

Abstract

Pb2KNb5O15 crystallizes in the orthorhombic Pmc2_1 space group. The structure is three-dimensional. K1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of K–O bond distances ranging from 2.88–3.04 Å. There are five 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 and faces with two equivalent PbO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 3–39°. There are a spread of Nb–O bond distances ranging from 1.86–2.17 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six NbO6 octahedra and faces with two equivalent PbO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 4–34°. There are a spread of Nb–O bond distances ranging from 1.91–2.21 Å. In the third Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share corners with six NbO6 octahedra and faces with two equivalent PbO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 7–39°. There are a spread of Nb–O bond distances ranging from 1.89–2.26 Å. In the fourth Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six NbO6 octahedra and faces with two equivalent PbO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 3–40°. There are a spread of Nb–O bond distances ranging from 1.89–2.18 Å. In the fifth Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 16–40°. There are a spread of Nb–O bond distances ranging from 1.87–2.18 Å. There are two inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded to twelve O2- atoms to form distorted PbO12 cuboctahedra that share faces with two equivalent PbO12 cuboctahedra and faces with eight NbO6 octahedra. There are a spread of Pb–O bond distances ranging from 2.59–3.07 Å. In the second Pb2+ site, Pb2+ is bonded in a 11-coordinate geometry to eleven O2- atoms. There are a spread of Pb–O bond distances ranging from 2.43–3.24 Å. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to two equivalent Nb5+ and two Pb2+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to two equivalent Nb5+ and one Pb2+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Nb5+ and one Pb2+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Nb5+ and two Pb2+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Nb5+ and two equivalent Pb2+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+ and two Nb5+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Nb5+ and two equivalent Pb2+ atoms. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent K1+ and two Nb5+ atoms. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent K1+ and two Nb5+ atoms. In the tenth O2- site, O2- is bonded to two Nb5+ and two equivalent Pb2+ atoms to form distorted corner-sharing ONb2Pb2 tetrahedra. In the eleventh O2- site, O2- is bonded in a distorted linear geometry to two Nb5+ and four Pb2+ atoms. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to two Nb5+ and two equivalent Pb2+ atoms. In the thirteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Nb5+ and two equivalent Pb2+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted linear geometry to two Nb5+ and two equivalent Pb2+ atoms. In the fifteenth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Nb5+ and one Pb2+ atom.