Materials Data on KAl3(SO7)2 by Materials Project

Abstract

KAl3(SO7)2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. K is bonded to twelve O atoms to form KO12 cuboctahedra that share corners with six equivalent SO4 tetrahedra and faces with six equivalent AlO6 octahedra. There are six shorter (2.89 Å) and six longer (2.98 Å) K–O bond lengths. Al is bonded to six O atoms to form AlO6 octahedra that share corners with four equivalent AlO6 octahedra, corners with two equivalent SO4 tetrahedra, and faces with two equivalent KO12 cuboctahedra. The corner-sharing octahedral tilt angles are 38°. There is four shorter (1.85 Å) and two longer (2.01 Å) Al–O bond length. S is bonded to four O atoms to form SO4 tetrahedra that share corners with three equivalent KO12 cuboctahedra and corners with three equivalent AlO6 octahedra. The corner-sharing octahedral tilt angles are 51°. There is one shorter (1.43 Å) and three longer (1.51 Å) S–O bond length. There are three inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one S atom. In the second O site, O is bonded in a 2-coordinate geometry to one K, one Al, and one S atom. In the third O site, O is bonded in a distorted bent 150 degrees geometry to one K and two equivalent Al atoms.