Materials Data on Ti4Pb2O9F2 by Materials Project
Ti4Pb2O9F2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to five O2- and one F1- atom to form distorted TiO5F octahedra that share corners with four TiO5F octahedra and edges with two equivalent TiO6 octahedra. The corner-sharing octahedra tilt angles range from 0–29°. There are a spread of Ti–O bond distances ranging from 1.77–2.11 Å. The Ti–F bond length is 2.37 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 17–18°. There are a spread of Ti–O bond distances ranging from 1.92–2.03 Å. Pb2+ is bonded in a 5-coordinate geometry to two equivalent O2- and three equivalent F1- atoms. Both Pb–O bond lengths are 2.52 Å. There are one shorter (2.44 Å) and two longer (2.59 Å) Pb–F bond lengths. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted T-shaped geometry to three Ti4+ atoms. In the second O2- site, O2- is bonded in a distorted T-shaped geometry to three Ti4+ atoms. In the third O2- site, O2- is bonded in a linear geometry to two equivalent Ti4+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ti4+ and two equivalent Pb2+ atoms. In the fifth O2- site, O2- is bonded in a distorted linear geometry to two Ti4+ atoms. F1- is bonded in a 4-coordinate geometry to one Ti4+ and three equivalent Pb2+ atoms.