DOE OSTI2020
Li2Fe(BO3)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Li sites. In the first Li site, Li is bonded to six O atoms to form LiO6 octahedra that share edges with two equivalent FeO6 octahedra and edges with four equivalent LiO6 octahedra. There are a spread of Li–O bond distances ranging from 2.01–2.33 Å. In the second Li site, Li is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Li–O bond distances ranging from 1.94–2.29 Å. Fe is bonded to six O atoms to form FeO6 octahedra that share edges with two equivalent LiO6 octahedra and edges with two equivalent FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.92–2.13 Å. There are two inequivalent B sites. In the first B site, B is bonded in a trigonal planar geometry to three O atoms. There are a spread of B–O bond distances ranging from 1.34–1.42 Å. In the second B site, B is bonded in a trigonal planar geometry to three O atoms. There are a spread of B–O bond distances ranging from 1.35–1.40 Å. There are six inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to one Li and two B atoms. In the second O site, O is bonded in a distorted rectangular see-saw-like geometry to two equivalent Li, one Fe, and one B atom. In the third O site, O is bonded to two equivalent Li, one Fe, and one B atom to form distorted OLi2FeB tetrahedra that share corners with two equivalent OLi2FeB tetrahedra and corners with four equivalent OLi2Fe2 trigonal pyramids. In the fourth O site, O is bonded in a distorted rectangular see-saw-like geometry to one Li, two equivalent Fe, and one B atom. In the fifth O site, O is bonded in a distorted rectangular see-saw-like geometry to three equivalent Li and one B atom. In the sixth O site, O is bonded to two Li and two equivalent Fe atoms to form OLi2Fe2 trigonal pyramids that share corners with four equivalent OLi2FeB tetrahedra and corners with two equivalent OLi2Fe2 trigonal pyramids.