DOI: 10.17188/1266417
title: Materials Data on Rb4Nb2Si8O23 by Materials Project

description: Rb4Nb2Si8O23 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Rb1+ sites. In the first Rb1+ site, Rb1+ is bonded in a 5-coordinate geometry to eleven O2- atoms. There are a spread of Rb–O bond distances ranging from 2.96–3.53 Å. In the second Rb1+ site, Rb1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Rb–O bond distances ranging from 2.95–3.34 Å. Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with five SiO4 tetrahedra. There are a spread of Nb–O bond distances ranging from 1.80–2.26 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one NbO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one NbO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one NbO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 6°. There are a spread of Si–O bond distances ranging from 1.59–1.65 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent NbO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 38–43°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Rb1+, one Nb5+, and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three Rb1+ and one Nb5+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Rb1+, one Nb5+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Rb1+ and two Si4+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Rb1+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Rb1+ and two Si4+ atoms. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to two Rb1+, one Nb5+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a distorted linear geometry to one Rb1+ and two Si4+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Rb1+ and two Si4+ atoms. In the tenth O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the eleventh O2- site, O2- is bonded in a linear geometry to two equivalent Rb1+, one Nb5+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Rb1+, one Nb5+, and one Si4+ atom.