Materials Data on Sr3Fe2O7 by Materials Project
Sr3Fe2O7 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Sr sites. In the first Sr site, Sr is bonded in a 9-coordinate geometry to nine O atoms. There are a spread of Sr–O bond distances ranging from 2.50–2.79 Å. In the second Sr site, Sr is bonded to twelve O atoms to form SrO12 cuboctahedra that share corners with four equivalent SrO12 cuboctahedra, faces with four equivalent SrO12 cuboctahedra, and faces with eight equivalent FeO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.75–2.78 Å. Fe is bonded to six O atoms to form FeO6 octahedra that share corners with five equivalent FeO6 octahedra and faces with four equivalent SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Fe–O bond distances ranging from 1.95–1.97 Å. There are three inequivalent O sites. In the first O site, O is bonded to four Sr and two equivalent Fe atoms to form a mixture of distorted edge, face, and corner-sharing OSr4Fe2 octahedra. The corner-sharing octahedra tilt angles range from 0–60°. In the second O site, O is bonded to five equivalent Sr and one Fe atom to form distorted OSr5Fe octahedra that share corners with seventeen OSr4Fe2 octahedra, edges with eight equivalent OSr5Fe octahedra, and faces with four equivalent OSr4Fe2 octahedra. The corner-sharing octahedra tilt angles range from 0–55°. In the third O site, O is bonded to four equivalent Sr and two equivalent Fe atoms to form a mixture of distorted edge, face, and corner-sharing OSr4Fe2 octahedra. The corner-sharing octahedra tilt angles range from 0–60°.