Materials Data on KNb(PO4)2 by Materials Project

Abstract

KNb(PO4)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. K1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.65–3.39 Å. Nb5+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share corners with five PO4 tetrahedra. There are a spread of Nb–O bond distances ranging from 1.76–2.30 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent NbO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 23–30°. There are a spread of P–O bond distances ranging from 1.50–1.62 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent NbO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 29–31°. There are a spread of P–O bond distances ranging from 1.49–1.63 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to one K1+, one Nb5+, and one P5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb5+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent K1+ and one Nb5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Nb5+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb5+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two P5+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Nb5+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to three equivalent K1+ and one P5+ atom.