Materials Data on B9Pb8O21F by Materials Project
Pb8B9O21F crystallizes in the trigonal R-3c space group. The structure is three-dimensional. there are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There is two shorter (1.46 Å) and two longer (1.51 Å) B–O bond length. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.37–1.40 Å. There are two inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded in a 3-coordinate geometry to nine O2- atoms. There are a spread of Pb–O bond distances ranging from 2.43–3.24 Å. In the second Pb2+ site, Pb2+ is bonded in a 6-coordinate geometry to five O2- and one F1- atom. There are a spread of Pb–O bond distances ranging from 2.27–2.88 Å. The Pb–F bond length is 2.97 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one B3+ and two Pb2+ atoms. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one B3+ and three Pb2+ atoms. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two B3+ and two Pb2+ atoms. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent B3+ and two equivalent Pb2+ atoms. F1- is bonded in an octahedral geometry to six equivalent Pb2+ atoms.