Materials Data on K3NbP2O9 by Materials Project
K3NbP2O9 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.66–3.13 Å. In the second K1+ site, K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.73–3.29 Å. In the third K1+ site, K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.80–3.19 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 1.78–2.41 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 two equivalent NbO6 octahedra. The corner-sharing octahedra tilt angles range from 30–40°. There is two shorter (1.52 Å) and two longer (1.60 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent NbO6 octahedra. The corner-sharing octahedra tilt angles range from 25–46°. There are a spread of P–O bond distances ranging from 1.52–1.58 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two K1+, one Nb5+, and one P5+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to four K1+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Nb5+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Nb5+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to four K1+ and one Nb5+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent K1+, one Nb5+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to four K1+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Nb5+, and one P5+ atom.