Materials Data on NaNb4(PO4)6 by Materials Project
NaNb4(PO4)6 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Na1+ is bonded in a distorted hexagonal planar geometry to six equivalent O2- atoms. All Na–O bond lengths are 2.53 Å. There are two inequivalent Nb+4.25+ sites. In the first Nb+4.25+ site, Nb+4.25+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six equivalent PO4 tetrahedra. There are three shorter (2.02 Å) and three longer (2.09 Å) Nb–O bond lengths. In the second Nb+4.25+ site, Nb+4.25+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six equivalent PO4 tetrahedra. There are three shorter (2.02 Å) and three longer (2.03 Å) Nb–O bond lengths. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four NbO6 octahedra. The corner-sharing octahedra tilt angles range from 22–36°. There is three shorter (1.54 Å) and one longer (1.55 Å) P–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb+4.25+ and one P5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb+4.25+ and one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Nb+4.25+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb+4.25+ and one P5+ atom.