DOE OSTI2020
LiFe6Ge4 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Li is bonded to twelve Fe and eight Ge atoms to form distorted face-sharing LiFe12Ge8 hexagonal bipyramids. All Li–Fe bond lengths are 3.25 Å. There are two shorter (2.48 Å) and six longer (2.91 Å) Li–Ge bond lengths. There are three inequivalent Fe sites. In the first Fe site, Fe is bonded in a 5-coordinate geometry to two equivalent Li, six Fe, and five Ge atoms. There are a spread of Fe–Fe bond distances ranging from 2.46–2.80 Å. There are a spread of Fe–Ge bond distances ranging from 2.48–2.56 Å. In the second Fe site, Fe is bonded in a 5-coordinate geometry to two equivalent Li, six equivalent Fe, and five Ge atoms. There are a spread of Fe–Ge bond distances ranging from 2.48–2.56 Å. In the third Fe site, Fe is bonded in a 5-coordinate geometry to two equivalent Li, six equivalent Fe, and five Ge atoms. Both Fe–Li bond lengths are 3.25 Å. There are a spread of Fe–Fe bond distances ranging from 2.46–2.80 Å. There are a spread of Fe–Ge bond distances ranging from 2.48–2.56 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 1-coordinate geometry to one Li and nine Fe atoms. In the second Ge site, Ge is bonded in a 12-coordinate geometry to three equivalent Li and six Fe atoms.