Materials Data on CaAlSiHO5 by Materials Project

Abstract

CaAlSiO4OH is Esseneite-derived structured and crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.54 Å. Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four equivalent SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–2.09 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 40–57°. There are a spread of Si–O bond distances ranging from 1.63–1.70 Å. H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.03 Å) and one longer (1.51 Å) H–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+, one Al3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to one Ca2+, two equivalent Al3+, and one H1+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+, one Al3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two equivalent Al3+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ca2+, one Si4+, and one H1+ atom.