Materials Data on CrH5O4 by Materials Project

Cr(OH)3.H2O crystallizes in the monoclinic Pm space group. The structure is two-dimensional and consists of one Cr(OH)3.H2O sheet oriented in the (0, 0, 1) direction. Cr3+ is bonded to six O2- atoms to form edge-sharing CrO6 octahedra. There are a spread of Cr–O bond distances ranging from 2.02–2.12 Å. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a distorted single-bond geometry to two O2- atoms. There is one shorter (1.03 Å) and one longer (1.58 Å) H–O bond length. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to two O2- atoms. There is one shorter (1.00 Å) and one longer (1.73 Å) H–O bond length. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Cr3+ and three H1+ atoms. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Cr3+ and one H1+ atom. In the third O2- site, O2- is bonded in a distorted L-shaped geometry to one Cr3+ and two equivalent H1+ atoms. In the fourth O2- site, O2- is bonded in a distorted water-like geometry to one Cr3+ and two H1+ atoms.