Materials Data on FeP2H2O9 by Materials Project
(FeP2(HO4)2)2O2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of four water molecules and one FeP2(HO4)2 framework. In the FeP2(HO4)2 framework, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.98–2.08 Å. There are two inequivalent P sites. In the first P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with three equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 21–45°. There are a spread of P–O bond distances ranging from 1.52–1.58 Å. In the second P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with three equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 26–52°. There are a spread of P–O bond distances ranging from 1.53–1.58 Å. There are two inequivalent H sites. In the first H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the second H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to one P and one H atom. In the second O site, O is bonded in a bent 150 degrees geometry to one Fe and one P atom. In the third O site, O is bonded in a 2-coordinate geometry to one Fe and one P atom. In the fourth O site, O is bonded in a bent 150 degrees geometry to one Fe and one P atom. In the fifth O site, O is bonded in a bent 120 degrees geometry to one P and one H atom. In the sixth O site, O is bonded in a bent 150 degrees geometry to one Fe and one P atom. In the seventh O site, O is bonded in a bent 150 degrees geometry to one Fe and one P atom. In the eighth O site, O is bonded in a distorted bent 150 degrees geometry to one Fe and one P atom.