Materials Data on CaAl6H12(SO7)4 by Materials Project

Abstract

CaAl6H12(SO7)4 crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three CaAl6H12(SO7)4 sheets oriented in the (0, 0, 1) direction. Ca2+ is bonded to twelve O2- atoms to form CaO12 cuboctahedra that share corners with six equivalent SO4 tetrahedra and faces with six equivalent AlO6 octahedra. There are six shorter (2.65 Å) and six longer (2.81 Å) Ca–O bond lengths. Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four equivalent AlO6 octahedra, corners with two SO4 tetrahedra, and a faceface with one CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 43–46°. There are a spread of Al–O bond distances ranging from 1.88–2.00 Å. There are two 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 single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are two inequivalent S6+ sites. In the first S6+ site, S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with three equivalent AlO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There is one shorter (1.46 Å) and three longer (1.50 Å) S–O bond length. In the second S6+ site, S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with three equivalent CaO12 cuboctahedra and corners with three equivalent AlO6 octahedra. The corner-sharing octahedral tilt angles are 52°. There is one shorter (1.47 Å) and three longer (1.50 Å) S–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one S6+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one S6+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one Al3+ and one S6+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to one Ca2+, two equivalent Al3+, and one H1+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ca2+, one Al3+, and one S6+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Al3+ and one H1+ atom.