Materials Data on LiAl(SiO3)2 by Materials Project

Abstract

LiAlSi2O6 is Esseneite-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.09–2.56 Å. Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.84–2.05 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent AlO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 27–60°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent AlO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 42–58°. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Li1+, one Al3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Li1+ and two equivalent Si4+ atoms. In the third O2- site, O2- is bonded to one Li1+, two equivalent Al3+, and one Si4+ atom to form a mixture of distorted edge and corner-sharing OLiAl2Si trigonal pyramids. In the fourth O2- site, O2- is bonded in a distorted T-shaped geometry to one Li1+, one Al3+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+ and two equivalent Si4+ atoms. In the sixth O2- site, O2- is bonded to one Li1+, two equivalent Al3+, and one Si4+ atom to form a mixture of distorted edge and corner-sharing OLiAl2Si trigonal pyramids.