DOI: 10.17188/1283398
title: Materials Data on Rb2NaNb6(PO8)3 by Materials Project

description: NaRb2Nb6P3O24 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. Rb1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Rb–O bond distances ranging from 3.10–3.41 Å. Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are four shorter (2.48 Å) and two longer (2.49 Å) Na–O bond lengths. There are three inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with four NbO6 octahedra and corners with two equivalent PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 4–35°. There are a spread of Nb–O bond distances ranging from 1.88–2.13 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with four NbO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 4–36°. There are a spread of Nb–O bond distances ranging from 1.88–2.16 Å. In the third Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with four NbO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 5–36°. There are a spread of Nb–O bond distances ranging from 1.88–2.14 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 four NbO6 octahedra. The corner-sharing octahedra tilt angles range from 39–41°. There is two shorter (1.54 Å) and two longer (1.56 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 39–41°. There is two shorter (1.54 Å) and two longer (1.56 Å) P–O bond length. There are thirteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two Nb5+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Rb1+ and two Nb5+ atoms. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Rb1+ and two Nb5+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Rb1+ and two equivalent Nb5+ atoms. In the fifth O2- site, O2- is bonded in a linear geometry to two equivalent Nb5+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Nb5+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Nb5+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Nb5+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Rb1+ and two Nb5+ atoms. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to one Rb1+, one Na1+, one Nb5+, and one P5+ atom. In the eleventh O2- site, O2- is bonded in a 2-coordinate geometry to one Rb1+, one Nb5+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to one Rb1+, one Nb5+, and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Rb1+ and two Nb5+ atoms.