Materials Data on KNb3(PO5)3 by Materials Project
KNb3P3O15 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.94–3.45 Å. There are three inequivalent Nb+4.67+ sites. In the first Nb+4.67+ site, Nb+4.67+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two NbO6 octahedra and corners with four PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are a spread of Nb–O bond distances ranging from 1.89–2.09 Å. In the second Nb+4.67+ site, Nb+4.67+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two NbO6 octahedra and corners with four PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 0–25°. There are a spread of Nb–O bond distances ranging from 1.92–2.12 Å. In the third Nb+4.67+ site, Nb+4.67+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two NbO6 octahedra and corners with four PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 5–25°. There are a spread of Nb–O bond distances ranging from 1.89–2.09 Å. There are three inequivalent P5+ sites. In the first P5+ site, 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 37–43°. There is one shorter (1.52 Å) and three longer (1.55 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 four NbO6 octahedra. The corner-sharing octahedra tilt angles range from 3–33°. There are a spread of P–O bond distances ranging from 1.53–1.56 Å. In the third P5+ site, 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 10–37°. There are a spread of P–O bond distances ranging from 1.53–1.56 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two Nb+4.67+ atoms. In the second O2- site, O2- is bonded in a linear geometry to one Nb+4.67+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Nb+4.67+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to one Nb+4.67+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb+4.67+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Nb+4.67+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb+4.67+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Nb+4.67+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Nb+4.67+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb+4.67+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Nb+4.67+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a linear geometry to two equivalent Nb+4.67+ atoms. In the thirteenth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Nb+4.67+, and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Nb+4.67+, and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a linear geometry to two equivalent Nb+4.67+ atoms. In the sixteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one K1+ and two Nb+4.67+ atoms.