Materials Data on Nb2FeS4 by Materials Project
FeNb2S4 crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one FeNb2S4 sheet oriented in the (0, 0, 1) direction. Nb+2.50+ is bonded to six S2- atoms to form distorted NbS6 pentagonal pyramids that share corners with six equivalent FeS6 octahedra, edges with six equivalent NbS6 pentagonal pyramids, and a faceface with one FeS6 octahedra. The corner-sharing octahedral tilt angles are 48°. There are three shorter (2.49 Å) and three longer (2.54 Å) Nb–S bond lengths. Fe3+ is bonded to six equivalent S2- atoms to form FeS6 octahedra that share corners with twelve equivalent NbS6 pentagonal pyramids, edges with six equivalent FeS6 octahedra, and faces with two equivalent NbS6 pentagonal pyramids. All Fe–S bond lengths are 2.29 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Nb+2.50+ atoms. In the second S2- site, S2- is bonded in a 6-coordinate geometry to three equivalent Nb+2.50+ and three equivalent Fe3+ atoms.