Materials Data on Na2VFeF7 by Materials Project

Abstract

Na2VFeF7 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are six inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a distorted body-centered cubic geometry to eight F1- atoms. There are a spread of Na–F bond distances ranging from 2.46–2.88 Å. In the second Na1+ site, Na1+ is bonded to eight F1- atoms to form distorted NaF8 hexagonal bipyramids that share corners with two equivalent NaF8 hexagonal bipyramids, corners with two equivalent VF6 octahedra, edges with two equivalent VF6 octahedra, and edges with four FeF6 octahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of Na–F bond distances ranging from 2.24–2.84 Å. In the third Na1+ site, Na1+ is bonded in a distorted body-centered cubic geometry to eight F1- atoms. There are a spread of Na–F bond distances ranging from 2.49–2.87 Å. In the fourth Na1+ site, Na1+ is bonded in a distorted body-centered cubic geometry to eight F1- atoms. There are a spread of Na–F bond distances ranging from 2.44–2.87 Å. In the fifth Na1+ site, Na1+ is bonded to eight F1- atoms to form distorted NaF8 hexagonal bipyramids that share a cornercorner with one NaF8 hexagonal bipyramid, a cornercorner with one VF6 octahedra, edges with three NaF8 hexagonal bipyramids, edges with three VF6 octahedra, and edges with three FeF6 octahedra. The corner-sharing octahedral tilt angles are 48°. There are a spread of Na–F bond distances ranging from 2.32–2.88 Å. In the sixth Na1+ site, Na1+ is bonded to eight F1- atoms to form distorted NaF8 hexagonal bipyramids that share corners with two NaF8 hexagonal bipyramids, corners with two VF6 octahedra, an edgeedge with one NaF8 hexagonal bipyramid, edges with two equivalent VF6 octahedra, and edges with four FeF6 octahedra. The corner-sharing octahedra tilt angles range from 49–57°. There are a spread of Na–F bond distances ranging from 2.19–2.92 Å. There are three inequivalent V2+ sites. In the first V2+ site, V2+ is bonded to six F1- atoms to form VF6 octahedra that share corners with two equivalent NaF8 hexagonal bipyramids, corners with four FeF6 octahedra, and edges with two equivalent NaF8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 40–42°. There are a spread of V–F bond distances ranging from 1.96–2.01 Å. In the second V2+ site, V2+ is bonded to six F1- atoms to form VF6 octahedra that share corners with two equivalent NaF8 hexagonal bipyramids, corners with four FeF6 octahedra, and edges with four equivalent NaF8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 43–46°. There are a spread of V–F bond distances ranging from 1.96–2.00 Å. In the third V2+ site, V2+ is bonded to six F1- atoms to form VF6 octahedra that share corners with two NaF8 hexagonal bipyramids, corners with four FeF6 octahedra, and edges with three NaF8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 44–47°. There are a spread of V–F bond distances ranging from 1.96–1.99 Å. 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, corners with four VF6 octahedra, and edges with four NaF8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 40–50°. There are a spread of Fe–F bond distances ranging from 2.06–2.09 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, corners with four VF6 octahedra, and edges with five NaF8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 42–50°. There are a spread of Fe–F bond distances ranging from 2.06–2.09 Å. There are fourteen inequivalent F1- sites. In the first F1- site, F1- is bonded in a 2-coordinate geometry to two Na1+, one V2+, and one Fe3+ atom. In the second F1- site, F1- is bonded in a 4-coordinate geometry to two Na1+, one V2+, and one Fe3+ atom. In the third F1- site, F1- is bonded in a 4-coordinate geometry to two Na1+, one V2+, and one Fe3+ atom. In the fourth F1- site, F1- is bonded in a 4-coordinate geometry to two Na1+, one V2+, and one Fe3+ atom. In the fifth F1- site, F1- is bonded in a 4-coordinate geometry to two Na1+, one V2+, and one Fe3+ atom. In the sixth F1- site, F1- is bonded in a 4-coordinate geometry to two equivalent Na1+, one V2+, and one Fe3+ atom. In the seventh F1- site, F1- is bonded in a 4-coordinate geometry to two Na1+, one V2+, and one Fe3+ atom. In the eighth F1- site, F1- is bonded in a 4-coordinate geometry to two Na1+, one V2+, and one Fe3+ atom. In the ninth F1- site, F1- is bonded in a 2-coordinate geometry to two Na1+ and two Fe3+ atoms. In the tenth F1- site, F1- is bonded in a 2-coordinate geometry to two Na1+ and two Fe3+ atoms. In the eleventh F1- site, F1- is bonded to three Na1+ and one V2+ atom to form a mixture of distorted edge and corner-sharing FNa3V tetrahedra. In the twelfth F1- site, F1- is bonded to three Na1+ and one V2+ atom to form a mixture of distorted edge and corner-sharing FNa3V tetrahedra. In the thirteenth F1- site, F1- is bonded in a 4-coordinate geometry to three Na1+ and one V2+ atom. In the fourteenth F1- site, F1- is bonded to three Na1+ and one V2+ atom to form a mixture of distorted edge and corner-sharing FNa3V tetrahedra.