Materials Data on Ta9Pb12O20F29 by Materials Project

Abstract

Pb12Ta9O20F29 crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. there are three inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to five O2- and one F1- atom to form corner-sharing TaO5F octahedra. The corner-sharing octahedra tilt angles range from 4–19°. There are a spread of Ta–O bond distances ranging from 1.91–2.00 Å. The Ta–F bond length is 2.11 Å. In the second Ta5+ site, Ta5+ is bonded to four O2- and two F1- atoms to form corner-sharing TaO4F2 octahedra. The corner-sharing octahedra tilt angles range from 4–19°. There are a spread of Ta–O bond distances ranging from 1.88–1.99 Å. There are one shorter (2.09 Å) and one longer (2.10 Å) Ta–F bond lengths. In the third Ta5+ site, Ta5+ is bonded to four equivalent O2- and two equivalent F1- atoms to form corner-sharing TaO4F2 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. All Ta–O bond lengths are 1.94 Å. Both Ta–F bond lengths are 1.96 Å. There are three inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded in a 6-coordinate geometry to six F1- atoms. There are a spread of Pb–F bond distances ranging from 2.32–2.77 Å. In the second Pb2+ site, Pb2+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of Pb–F bond distances ranging from 2.48–2.82 Å. In the third Pb2+ site, Pb2+ is bonded in a 5-coordinate geometry to five F1- atoms. There are a spread of Pb–F bond distances ranging from 2.32–2.57 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Ta5+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to two equivalent Ta5+ atoms. In the third O2- site, O2- is bonded in a linear geometry to two Ta5+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the fifth O2- site, O2- is bonded in a linear geometry to two Ta5+ atoms. There are eight inequivalent F1- sites. In the first F1- site, F1- is bonded to four Pb2+ atoms to form a mixture of edge and corner-sharing FPb4 tetrahedra. In the second F1- site, F1- is bonded in a trigonal planar geometry to three equivalent Pb2+ atoms. In the third F1- site, F1- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the fourth F1- site, F1- is bonded in a distorted single-bond geometry to one Ta5+ and two equivalent Pb2+ atoms. In the fifth F1- site, F1- is bonded in a 3-coordinate geometry to three Pb2+ atoms. In the sixth F1- site, F1- is bonded in a distorted single-bond geometry to one Ta5+ and two equivalent Pb2+ atoms. In the seventh F1- site, F1- is bonded in a distorted single-bond geometry to one Ta5+ and two equivalent Pb2+ atoms. In the eighth F1- site, F1- is bonded in a distorted trigonal non-coplanar geometry to three Pb2+ atoms.