Materials Data on FeP(HO2)2 by Materials Project

FeH2PO4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of four hydrogen molecules and one FeHPO4 framework. In the FeHPO4 framework, Fe3+ is bonded to one H and four O2- atoms to form distorted FeHO4 trigonal bipyramids that share corners with four equivalent PO4 tetrahedra. The Fe–H bond length is 1.62 Å. There are a spread of Fe–O bond distances ranging from 1.89–1.92 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four equivalent FeHO4 trigonal bipyramids. There is one shorter (1.53 Å) and three longer (1.55 Å) P–O bond length. H is bonded in a distorted single-bond geometry to one Fe3+ atom. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom.