Materials Data on K2CeNb5O15 by Materials Project

Abstract

K2CeNb5O15 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. K1+ is bonded in a 6-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.86–3.25 Å. Ce3+ is bonded to twelve O2- atoms to form CeO12 cuboctahedra that share faces with two equivalent CeO12 cuboctahedra and faces with eight equivalent NbO6 octahedra. There are four shorter (2.62 Å) and eight longer (2.71 Å) Ce–O bond lengths. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six NbO6 octahedra and faces with two equivalent CeO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 12–36°. There are a spread of Nb–O bond distances ranging from 1.92–2.08 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 0–32°. There are two shorter (1.99 Å) and four longer (2.02 Å) Nb–O bond lengths. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+ and two equivalent Nb5+ atoms. In the second O2- site, O2- is bonded in a linear geometry to two equivalent K1+ and two equivalent Nb5+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ce3+ and two equivalent Nb5+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Ce3+, and two equivalent Nb5+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent K1+ and two Nb5+ atoms.