DOE OSTI2020
PbTi3O7 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are three inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 22°. There are a spread of Ti–O bond distances ranging from 1.86–2.08 Å. In the second Ti4+ site, Ti4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ti–O bond distances ranging from 1.78–2.33 Å. In the third Ti4+ site, Ti4+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 24°. There are a spread of Ti–O bond distances ranging from 1.83–2.12 Å. Pb2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Pb–O bond distances ranging from 2.40–2.59 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted T-shaped geometry to three equivalent 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 to four Ti4+ atoms to form a mixture of distorted corner and edge-sharing OTi4 trigonal pyramids. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to one Ti4+ and three equivalent Pb2+ atoms. In the fifth O2- site, O2- is bonded in a distorted linear geometry to two Ti4+ atoms. In the sixth O2- site, O2- is bonded in a distorted T-shaped geometry to three Ti4+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two Ti4+ and two equivalent Pb2+ atoms.