Materials Data on CaAs(HO)7 by Materials Project
CaAs(HO)7 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with three equivalent AsO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.28–2.46 Å. As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with three equivalent CaO6 octahedra. The corner-sharing octahedra tilt angles range from 27–55°. There are a spread of As–O bond distances ranging from 1.68–1.78 Å. There are seven inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the second H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.02 Å) and one longer (1.58 Å) H–O bond length. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to two O2- atoms. There is one shorter (1.00 Å) and one longer (1.77 Å) H–O bond length. In the fifth 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 sixth 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 seventh H1+ site, 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 2-coordinate geometry to one As5+ and one H1+ atom. In the second O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+ and two H1+ atoms. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Ca2+ and one As5+ atom. In the fourth O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+ and two H1+ atoms. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, one As5+, and two H1+ atoms. In the sixth O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+ and two H1+ atoms. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one As5+, and one H1+ atom.