Materials Data on CaAsHO5 by Materials Project
CaAsHO5 crystallizes in the orthorhombic Pbcn space group. The structure is two-dimensional and consists of two CaAsHO5 sheets oriented in the (0, 0, 1) direction. Ca is bonded to seven O atoms to form distorted CaO7 pentagonal bipyramids that share corners with two equivalent CaO7 pentagonal bipyramids, corners with four equivalent AsO4 tetrahedra, edges with three equivalent CaO7 pentagonal bipyramids, and an edgeedge with one AsO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.33–2.74 Å. As is bonded to four O atoms to form AsO4 tetrahedra that share corners with four equivalent CaO7 pentagonal bipyramids and an edgeedge with one CaO7 pentagonal bipyramid. There are a spread of As–O bond distances ranging from 1.70–1.75 Å. H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.01 Å) and one longer (1.68 Å) H–O bond length. There are five inequivalent O sites. In the first O site, O is bonded in a distorted trigonal non-coplanar geometry to two equivalent Ca and one As atom. In the second O site, O is bonded in a distorted trigonal non-coplanar geometry to one Ca, one As, and one H atom. In the third O site, O is bonded in a water-like geometry to one As and one H atom. In the fourth O site, O is bonded in a 4-coordinate geometry to three equivalent Ca and one As atom. In the fifth O site, O is bonded in a single-bond geometry to one Ca atom.