Materials Data on K3CaP2HO8 by Materials Project

Abstract

K3CaP2HO8 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to two equivalent H1+ and ten O2- atoms to form distorted KH2O10 cuboctahedra that share corners with two equivalent PO4 tetrahedra, edges with four equivalent PO4 tetrahedra, faces with two equivalent KH2O10 cuboctahedra, and faces with two equivalent CaO6 octahedra. Both K–H bond lengths are 2.91 Å. There are a spread of K–O bond distances ranging from 2.92–3.15 Å. 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 2.71–3.04 Å. Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six equivalent PO4 tetrahedra and faces with two equivalent KH2O10 cuboctahedra. There are four shorter (2.35 Å) and two longer (2.38 Å) Ca–O bond lengths. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one KH2O10 cuboctahedra, corners with three equivalent CaO6 octahedra, and edges with two equivalent KH2O10 cuboctahedra. The corner-sharing octahedra tilt angles range from 12–35°. There is three shorter (1.55 Å) and one longer (1.58 Å) P–O bond length. H1+ is bonded in a linear geometry to two equivalent K1+ and two equivalent O2- atoms. Both H–O bond lengths are 1.22 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to three K1+, one Ca2+, and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to three K1+, one P5+, and one H1+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to four K1+, one Ca2+, and one P5+ atom.