Materials Data on Nb2FeSe4 by Materials Project
Nb2FeSe4 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are three inequivalent Nb+2.50+ sites. In the first Nb+2.50+ site, Nb+2.50+ is bonded to six Se2- atoms to form distorted NbSe6 pentagonal pyramids that share faces with two equivalent FeSe6 octahedra. All Nb–Se bond lengths are 2.65 Å. In the second Nb+2.50+ site, Nb+2.50+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are two shorter (2.57 Å) and four longer (2.76 Å) Nb–Se bond lengths. In the third Nb+2.50+ site, Nb+2.50+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are two shorter (2.57 Å) and four longer (2.77 Å) Nb–Se bond lengths. There are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six Se2- atoms to form FeSe6 octahedra that share faces with two equivalent NbSe6 pentagonal pyramids. All Fe–Se bond lengths are 2.61 Å. In the second Fe3+ site, Fe3+ is bonded in a 6-coordinate geometry to six Se2- atoms. All Fe–Se bond lengths are 2.61 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to three Nb+2.50+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to three Nb+2.50+ and two Fe3+ atoms. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to three Nb+2.50+ and two Fe3+ atoms.