Materials Data on CaFe2P2HO9 by Materials Project
CaFe2P2HO9 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.99 Å. There are two inequivalent Fe+2.50+ sites. In the first Fe+2.50+ site, Fe+2.50+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with four PO4 tetrahedra, and edges with two equivalent FeO6 octahedra. The corner-sharing octahedral tilt angles are 56°. There are a spread of Fe–O bond distances ranging from 2.08–2.21 Å. In the second Fe+2.50+ site, Fe+2.50+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with five PO4 tetrahedra, and an edgeedge with one FeO6 octahedra. The corner-sharing octahedral tilt angles are 56°. There are a spread of Fe–O bond distances ranging from 1.96–2.16 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with five FeO6 octahedra. The corner-sharing octahedra tilt angles range from 43–59°. There is three shorter (1.55 Å) and one longer (1.58 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four FeO6 octahedra. The corner-sharing octahedra tilt angles range from 40–55°. There is one shorter (1.51 Å) and three longer (1.57 Å) P–O bond length. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Fe+2.50+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Fe+2.50+ and one P5+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two equivalent Fe+2.50+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Fe+2.50+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Fe+2.50+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to three Fe+2.50+ and one H1+ atom.