Materials Data on Nb3NiSe6 by Materials Project
Nb3NiSe6 is Ilmenite-like structured and crystallizes in the hexagonal P6_322 space group. The structure is three-dimensional. there are two inequivalent Nb+3.33+ sites. In the first Nb+3.33+ site, Nb+3.33+ is bonded to six equivalent Se2- atoms to form distorted NbSe6 pentagonal pyramids that share corners with six equivalent NiSe6 octahedra and edges with six equivalent NbSe6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 47°. All Nb–Se bond lengths are 2.61 Å. In the second Nb+3.33+ site, Nb+3.33+ is bonded to six equivalent Se2- atoms to form distorted NbSe6 pentagonal pyramids that share corners with three equivalent NiSe6 octahedra, edges with six NbSe6 pentagonal pyramids, and a faceface with one NiSe6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are three shorter (2.61 Å) and three longer (2.64 Å) Nb–Se bond lengths. Ni2+ is bonded to six equivalent Se2- atoms to form NiSe6 octahedra that share corners with twelve NbSe6 pentagonal pyramids and faces with two equivalent NbSe6 pentagonal pyramids. All Ni–Se bond lengths are 2.50 Å. Se2- is bonded in a distorted rectangular see-saw-like geometry to three Nb+3.33+ and one Ni2+ atom.