Materials Data on Li2FeF5 by Materials Project
Li2FeF5 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. there are four inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to five F1- atoms to form distorted LiF5 trigonal bipyramids that share corners with three FeF6 octahedra and an edgeedge with one FeF6 octahedra. The corner-sharing octahedra tilt angles range from 2–68°. There are a spread of Li–F bond distances ranging from 1.83–2.14 Å. In the second Li1+ site, Li1+ is bonded in a 5-coordinate geometry to five F1- atoms. There are a spread of Li–F bond distances ranging from 1.96–2.39 Å. In the third Li1+ site, Li1+ is bonded in a distorted rectangular see-saw-like geometry to four F1- atoms. There are a spread of Li–F bond distances ranging from 1.94–2.18 Å. In the fourth Li1+ site, Li1+ is bonded in a 3-coordinate geometry to three F1- atoms. There is one shorter (1.87 Å) and two longer (2.06 Å) Li–F bond length. There are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six F1- atoms to form FeF6 octahedra that share corners with two equivalent FeF6 octahedra, a cornercorner with one LiF5 trigonal bipyramid, and an edgeedge with one LiF5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 14°. There are a spread of Fe–F bond distances ranging from 1.88–1.98 Å. In the second Fe3+ site, Fe3+ is bonded to six F1- atoms to form FeF6 octahedra that share corners with two equivalent FeF6 octahedra and corners with two equivalent LiF5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 14°. There are a spread of Fe–F bond distances ranging from 1.93–1.98 Å. There are seven inequivalent F1- sites. In the first F1- site, F1- is bonded in a bent 150 degrees geometry to one Li1+ and one Fe3+ atom. In the second F1- site, F1- is bonded in a distorted trigonal planar geometry to two equivalent Li1+ and one Fe3+ atom. In the third F1- site, F1- is bonded in a 4-coordinate geometry to three Li1+ and one Fe3+ atom. In the fourth F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one Li1+ and one Fe3+ atom. In the fifth F1- site, F1- is bonded to three Li1+ and one Fe3+ atom to form distorted edge-sharing FLi3Fe tetrahedra. In the sixth F1- site, F1- is bonded in a linear geometry to one Li1+ and one Fe3+ atom. In the seventh F1- site, F1- is bonded in a distorted linear geometry to two Fe3+ atoms.