DOE OSTI2020
Cu3Sb(PO4)4 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are three inequivalent Cu+2.33+ sites. In the first Cu+2.33+ site, Cu+2.33+ is bonded to six O2- atoms to form CuO6 octahedra that share corners with four equivalent CuO6 octahedra, corners with four PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Cu–O bond distances ranging from 1.97–2.14 Å. In the second Cu+2.33+ site, Cu+2.33+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cu–O bond distances ranging from 1.89–2.47 Å. In the third Cu+2.33+ site, Cu+2.33+ is bonded to six O2- atoms to form distorted CuO6 octahedra that share corners with four equivalent CuO6 octahedra, corners with four PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Cu–O bond distances ranging from 1.93–2.32 Å. Sb5+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with four PO4 tetrahedra and an edgeedge with one PO4 tetrahedra. There are a spread of Sb–O bond distances ranging from 1.96–2.11 Å. There are four 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 SbO6 octahedra, corners with three CuO6 octahedra, and an edgeedge with one CuO6 octahedra. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of P–O bond distances ranging from 1.53–1.62 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, a cornercorner with one SbO6 octahedra, and an edgeedge with one SbO6 octahedra. The corner-sharing octahedra tilt angles range from 42–43°. There are a spread of P–O bond distances ranging from 1.50–1.60 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three CuO6 octahedra and an edgeedge with one CuO6 octahedra. The corner-sharing octahedra tilt angles range from 49–54°. There are a spread of P–O bond distances ranging from 1.53–1.58 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CuO6 octahedra and corners with two equivalent SbO6 octahedra. The corner-sharing octahedra tilt angles range from 49–54°. There are a spread of P–O bond distances ranging from 1.50–1.62 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Sb5+ and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Cu+2.33+ and one P5+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one Cu+2.33+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cu+2.33+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Cu+2.33+, one Sb5+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cu+2.33+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cu+2.33+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to two Cu+2.33+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Sb5+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a bent 120 degrees geometry to one Cu+2.33+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to one Cu+2.33+, one Sb5+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cu+2.33+ and one P5+ atom.