Materials Data on KNb5O13 by Materials Project

Abstract

KNb5O13 crystallizes in the orthorhombic Pbcm 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 2.77–3.09 Å. There are three inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form a mixture of distorted corner and edge-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 31–48°. There are a spread of Nb–O bond distances ranging from 1.88–2.27 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 16–48°. There are a spread of Nb–O bond distances ranging from 1.92–2.13 Å. In the third Nb5+ site, Nb5+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Nb–O bond distances ranging from 1.92–2.34 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to one K1+ and two equivalent Nb5+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two Nb5+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two Nb5+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two Nb5+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+ and two Nb5+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to three Nb5+ atoms. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three Nb5+ atoms.