Materials Data on SrAl2(SiO4)2 by Materials Project

Abstract

SrAl2Si2O8 crystallizes in the trigonal P-3c1 space group. The structure is three-dimensional. Sr2+ is bonded to six equivalent O2- atoms to form SrO6 octahedra that share corners with six equivalent AlO4 tetrahedra and corners with six equivalent SiO4 tetrahedra. All Sr–O bond lengths are 2.63 Å. Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent SrO6 octahedra and corners with four equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 64°. There is one shorter (1.71 Å) and three longer (1.78 Å) Al–O bond length. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent SrO6 octahedra and corners with four equivalent AlO4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. There is one shorter (1.60 Å) and three longer (1.65 Å) Si–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to one Al3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Sr2+, one Al3+, and one Si4+ atom.