DOE OSTI2020
TiCu(PO4)2 crystallizes in the trigonal R3 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 TiO6 octahedra that share corners with six PO4 tetrahedra. There is three shorter (1.90 Å) and three longer (1.99 Å) Ti–O bond length. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six PO4 tetrahedra. There is three shorter (1.90 Å) and three longer (2.02 Å) Ti–O bond length. In the third Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six PO4 tetrahedra. There is three shorter (1.89 Å) and three longer (2.03 Å) Ti–O bond length. There are three inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are three shorter (2.17 Å) and three longer (2.28 Å) Cu–O bond lengths. In the second Cu2+ site, Cu2+ is bonded to six O2- atoms to form CuO6 octahedra that share corners with six PO4 tetrahedra. There are three shorter (1.94 Å) and three longer (2.07 Å) Cu–O bond lengths. In the third Cu2+ site, Cu2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are three shorter (2.26 Å) and three longer (2.28 Å) Cu–O bond lengths. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CuO6 octahedra and corners with three TiO6 octahedra. The corner-sharing octahedra tilt angles range from 23–46°. There are a spread of P–O bond distances ranging from 1.50–1.57 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CuO6 octahedra and corners with three TiO6 octahedra. The corner-sharing octahedra tilt angles range from 22–48°. There are a spread of P–O bond distances ranging from 1.54–1.56 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Ti4+ and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ti4+, one Cu2+, and one P5+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Cu2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Ti4+, one Cu2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ti4+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two Cu2+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Ti4+, one Cu2+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ti4+ and one P5+ atom.