Materials Data on Ca5P8 by Materials Project

Abstract

Ca5P8 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six P+1.25- atoms to form CaP6 octahedra that share corners with four equivalent CaP6 octahedra, corners with two equivalent PP4 tetrahedra, edges with ten CaP6 octahedra, and edges with two equivalent PP4 tetrahedra. The corner-sharing octahedral tilt angles are 8°. There are four shorter (2.89 Å) and two longer (3.13 Å) Ca–P bond lengths. In the second Ca2+ site, Ca2+ is bonded to six P+1.25- atoms to form CaP6 octahedra that share corners with four equivalent CaP6 octahedra, corners with two equivalent PP4 tetrahedra, edges with ten CaP6 octahedra, and edges with two equivalent PP4 tetrahedra. The corner-sharing octahedral tilt angles are 9°. There are a spread of Ca–P bond distances ranging from 2.90–3.04 Å. In the third Ca2+ site, Ca2+ is bonded to six P+1.25- atoms to form CaP6 octahedra that share corners with six CaP6 octahedra, corners with six equivalent PP4 tetrahedra, and edges with nine CaP6 octahedra. The corner-sharing octahedra tilt angles range from 8–9°. There are four shorter (2.95 Å) and two longer (2.97 Å) Ca–P bond lengths. There are three inequivalent P+1.25- sites. In the first P+1.25- site, P+1.25- is bonded to five Ca2+ and one P+1.25- atom to form PCa5P octahedra that share corners with seven PCa5P octahedra, a cornercorner with one PP4 tetrahedra, and edges with ten PCa5P octahedra. The corner-sharing octahedra tilt angles range from 0–94°. The P–P bond length is 2.16 Å. In the second P+1.25- site, P+1.25- is bonded to five Ca2+ and one P+1.25- atom to form PCa5P octahedra that share corners with seven PCa5P octahedra, a cornercorner with one PP4 tetrahedra, and edges with ten PCa5P octahedra. The corner-sharing octahedra tilt angles range from 0–94°. The P–P bond length is 2.18 Å. In the third P+1.25- site, P+1.25- is bonded to four P+1.25- atoms to form distorted PP4 tetrahedra that share corners with three PCa5P octahedra, corners with nine CaP6 octahedra, and edges with three CaP6 octahedra. The corner-sharing octahedra tilt angles range from 21–76°. The P–P bond length is 2.34 Å.