Materials Data on KCa10(PO4)7 by Materials Project

Abstract

Ca10K(PO4)7 crystallizes in the trigonal R3c space group. The structure is three-dimensional. K1+ is bonded in a 3-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.69–3.24 Å. There are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six PO4 tetrahedra. There are three shorter (2.29 Å) and three longer (2.32 Å) Ca–O bond lengths. In the second Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.38–2.84 Å. In the third Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.36–2.55 Å. In the fourth Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.40–2.73 Å. There are three inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CaO6 octahedra. The corner-sharing octahedral tilt angles are 57°. There is three shorter (1.55 Å) and one 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 a cornercorner with one CaO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There is two shorter (1.55 Å) and two longer (1.57 Å) P–O bond length. In the third P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. All P–O bond lengths are 1.56 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to one K1+, two Ca2+, and one P5+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one P5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted tetrahedral geometry to three equivalent Ca2+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to one K1+, two Ca2+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a 1-coordinate geometry to one K1+, two Ca2+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one P5+ atom.