DOE OSTI2020
V3(O2F)2 is zeta iron carbide-derived structured and crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are six inequivalent V+3.33+ sites. In the first V+3.33+ site, V+3.33+ is bonded to four O2- and two equivalent F1- atoms to form VO4F2 octahedra that share corners with eight VO2F4 octahedra and edges with two equivalent VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 47–51°. There is two shorter (1.98 Å) and two longer (2.01 Å) V–O bond length. Both V–F bond lengths are 2.11 Å. In the second V+3.33+ site, V+3.33+ is bonded to two O2- and four equivalent F1- atoms to form VO2F4 octahedra that share corners with eight VO4F2 octahedra and edges with two equivalent VO2F4 octahedra. The corner-sharing octahedra tilt angles range from 50–52°. There is one shorter (1.91 Å) and one longer (1.98 Å) V–O bond length. All V–F bond lengths are 2.00 Å. In the third V+3.33+ site, V+3.33+ is bonded to five O2- and one F1- atom to form VO5F octahedra that share corners with eight VO4F2 octahedra and edges with two equivalent VO5F octahedra. The corner-sharing octahedra tilt angles range from 47–51°. There is one shorter (1.88 Å) and four longer (2.00 Å) V–O bond length. The V–F bond length is 2.16 Å. In the fourth V+3.33+ site, V+3.33+ is bonded to four O2- and two equivalent F1- atoms to form VO4F2 octahedra that share corners with eight VO2F4 octahedra and edges with two equivalent VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 50–51°. There is two shorter (1.98 Å) and two longer (2.01 Å) V–O bond length. Both V–F bond lengths are 2.00 Å. In the fifth V+3.33+ site, V+3.33+ is bonded to four O2- and two equivalent F1- atoms to form VO4F2 octahedra that share corners with eight VO2F4 octahedra and edges with two equivalent VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 47–52°. There is two shorter (1.89 Å) and two longer (1.95 Å) V–O bond length. Both V–F bond lengths are 2.10 Å. In the sixth V+3.33+ site, V+3.33+ is bonded to five O2- and one F1- atom to form VO5F octahedra that share corners with eight VO4F2 octahedra and edges with two equivalent VO5F octahedra. The corner-sharing octahedra tilt angles range from 47–51°. There are one shorter (1.94 Å) and four longer (2.08 Å) V–O bond lengths. The V–F bond length is 2.11 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three V+3.33+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three V+3.33+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to three V+3.33+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to three V+3.33+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to three V+3.33+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three V+3.33+ atoms. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted trigonal planar geometry to three V+3.33+ atoms. In the second F1- site, F1- is bonded in a 3-coordinate geometry to three V+3.33+ atoms. In the third F1- site, F1- is bonded in a 3-coordinate geometry to three V+3.33+ atoms.