Materials Data on K2ErTi(PO4)3 by Materials Project

Abstract

K2ErTi(PO4)3 crystallizes in the cubic P2_13 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are three shorter (2.98 Å) and three longer (3.24 Å) K–O bond lengths. In the second K1+ site, K1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.96–3.11 Å. Er3+ is bonded to six O2- atoms to form ErO6 octahedra that share corners with six equivalent PO4 tetrahedra. There are three shorter (2.17 Å) and three longer (2.19 Å) Er–O bond lengths. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six equivalent PO4 tetrahedra. There is three shorter (1.95 Å) and three longer (2.04 Å) Ti–O bond length. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent ErO6 octahedra and corners with two equivalent TiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–41°. There are a spread of P–O bond distances ranging from 1.52–1.58 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Er3+, and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two K1+, one Er3+, and one P5+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Ti4+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to one K1+, one Ti4+, and one P5+ atom.