Materials Data on LiFeAs2O7 by Materials Project
LiFeAs2O7 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 (2.07 Å) and two longer (2.13 Å) Li–O bond lengths. Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent AsO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.96–2.08 Å. As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with three equivalent FeO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 26–55°. There are a spread of As–O bond distances ranging from 1.69–1.78 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent As5+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Fe3+, and one As5+ atom. In the third O2- site, O2- is bonded in a trigonal planar geometry to one Li1+, one Fe3+, and one As5+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one As5+ atom.