Materials Data on LiAlAs2O7 by Materials Project

Abstract

LiAlAs2O7 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. Li1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are two shorter (2.04 Å) and two longer (2.06 Å) Li–O bond lengths. Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six equivalent AsO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.87–1.96 Å. As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with three equivalent AlO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 24–55°. There are a spread of As–O bond distances ranging from 1.68–1.78 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to one Li1+, one Al3+, and one As5+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Al3+, and one As5+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Al3+ and one As5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent As5+ atoms.