Materials Data on NbCu3(PO4)4 by Materials Project
NbCu3(PO4)4 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. Nb5+ is bonded to six O2- atoms to form distorted NbO6 pentagonal pyramids that share corners with four PO4 tetrahedra and an edgeedge with one PO4 tetrahedra. There are a spread of Nb–O bond distances ranging from 1.90–2.11 Å. 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 distorted CuO6 octahedra that share corners with four PO4 tetrahedra and an edgeedge with one PO4 tetrahedra. There are a spread of Cu–O bond distances ranging from 1.95–2.23 Å. In the second Cu+2.33+ site, Cu+2.33+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.88–2.04 Å. In the third 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 1.89–2.49 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 corners with two equivalent CuO6 octahedra and a cornercorner with one NbO6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 53°. There is three shorter (1.53 Å) and one longer (1.63 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one NbO6 pentagonal pyramid and an edgeedge with one NbO6 pentagonal pyramid. There are a spread of P–O bond distances ranging from 1.50–1.59 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CuO6 octahedra and an edgeedge with one CuO6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are a spread of P–O bond distances ranging from 1.53–1.57 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 NbO6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 47°. There are a spread of P–O bond distances ranging from 1.51–1.60 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb5+ and one P5+ atom. In the second O2- site, O2- is bonded in a 1-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 Nb5+, one Cu+2.33+, 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 bent 150 degrees geometry to one Nb5+ 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 distorted bent 120 degrees geometry to one Nb5+ 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.