DOE OSTI2020
Li2(FeO2)3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Li sites. In the first Li site, Li is bonded to six O atoms to form distorted LiO6 octahedra that share corners with nine FeO6 octahedra, edges with three equivalent LiO6 octahedra, edges with three FeO6 octahedra, and a faceface with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 8–55°. There are a spread of Li–O bond distances ranging from 2.08–2.40 Å. In the second Li site, Li is bonded to six O atoms to form distorted LiO6 octahedra that share corners with nine FeO6 octahedra, edges with three equivalent LiO6 octahedra, edges with three FeO6 octahedra, and a faceface with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 4–55°. There are a spread of Li–O bond distances ranging from 2.09–2.37 Å. In the third Li site, Li is bonded to six O atoms to form distorted LiO6 octahedra that share corners with nine FeO6 octahedra, edges with three equivalent LiO6 octahedra, edges with three FeO6 octahedra, and a faceface with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–53°. There are a spread of Li–O bond distances ranging from 2.10–2.31 Å. In the fourth Li site, Li is bonded to six O atoms to form LiO6 octahedra that share corners with nine FeO6 octahedra, edges with three equivalent LiO6 octahedra, edges with three FeO6 octahedra, and a faceface with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 3–53°. There are a spread of Li–O bond distances ranging from 2.11–2.28 Å. There are six inequivalent Fe sites. In the first Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with eight LiO6 octahedra, edges with two LiO6 octahedra, and edges with six FeO6 octahedra. The corner-sharing octahedra tilt angles range from 3–55°. There are a spread of Fe–O bond distances ranging from 2.00–2.18 Å. In the second Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with five LiO6 octahedra, edges with two LiO6 octahedra, edges with six FeO6 octahedra, and a faceface with one LiO6 octahedra. The corner-sharing octahedra tilt angles range from 11–46°. There are a spread of Fe–O bond distances ranging from 1.99–2.05 Å. In the third Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with five LiO6 octahedra, edges with two LiO6 octahedra, edges with six FeO6 octahedra, and a faceface with one LiO6 octahedra. The corner-sharing octahedra tilt angles range from 12–44°. There are a spread of Fe–O bond distances ranging from 1.96–2.08 Å. In the fourth Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with eight LiO6 octahedra, edges with two LiO6 octahedra, and edges with six FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–55°. There are a spread of Fe–O bond distances ranging from 2.00–2.19 Å. In the fifth Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with five LiO6 octahedra, edges with two LiO6 octahedra, edges with six FeO6 octahedra, and a faceface with one LiO6 octahedra. The corner-sharing octahedra tilt angles range from 9–45°. There are a spread of Fe–O bond distances ranging from 1.90–2.08 Å. In the sixth Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with five LiO6 octahedra, edges with two LiO6 octahedra, edges with six FeO6 octahedra, and a faceface with one LiO6 octahedra. The corner-sharing octahedra tilt angles range from 9–46°. There are a spread of Fe–O bond distances ranging from 1.91–2.07 Å. There are twelve inequivalent O sites. In the first O site, O is bonded to two Li and three Fe atoms to form a mixture of edge and corner-sharing OLi2Fe3 square pyramids. In the second O site, O is bonded to two Li and three Fe atoms to form a mixture of edge and corner-sharing OLi2Fe3 square pyramids. In the third O site, O is bonded to two Li and three Fe atoms to form a mixture of distorted edge and corner-sharing OLi2Fe3 trigonal bipyramids. In the fourth O site, O is bonded to two Li and three Fe atoms to form a mixture of distorted edge and corner-sharing OLi2Fe3 trigonal bipyramids. In the fifth O site, O is bonded to two Li and three Fe atoms to form a mixture of edge and corner-sharing OLi2Fe3 square pyramids. In the sixth O site, O is bonded to two Li and three Fe atoms to form a mixture of edge and corner-sharing OLi2Fe3 square pyramids. In the seventh O site, O is bonded in a 5-coordinate geometry to two Li and three Fe atoms. In the eighth O site, O is bonded to two Li and three Fe atoms to form a mixture of distorted edge and corner-sharing OLi2Fe3 trigonal bipyramids. In the ninth O site, O is bonded to two Li and three Fe atoms to form a mixture of edge and corner-sharing OLi2Fe3 square pyramids. In the tenth O site, O is bonded to two Li and three Fe atoms to form a mixture of edge and corner-sharing OLi2Fe3 square pyramids. In the eleventh O site, O is bonded to two Li and three Fe atoms to form a mixture of distorted edge and corner-sharing OLi2Fe3 trigonal bipyramids. In the twelfth O site, O is bonded to two Li and three Fe atoms to form a mixture of distorted edge and corner-sharing OLi2Fe3 trigonal bipyramids.