Nb3CrSe6 is Ilmenite-like structured and crystallizes in the hexagonal P6_322 space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to six equivalent Se(1) atoms to form distorted NbSe6 pentagonal pyramids that share corners with three equivalent Cr(1)Se6 octahedra, edges with three equivalent Nb(1)Se6 pentagonal pyramids, edges with three equivalent Nb(2)Se6 pentagonal pyramids, and  a faceface with one Cr(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 47°. In the second Nb site, Nb(2) is bonded to six equivalent Se(1) atoms to form distorted NbSe6 pentagonal pyramids that share corners with six equivalent Cr(1)Se6 octahedra and edges with six equivalent Nb(1)Se6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 46°. Cr(1) is bonded to six equivalent Se(1) atoms to form CrSe6 octahedra that share corners with six equivalent Nb(1)Se6 pentagonal pyramids, corners with six equivalent Nb(2)Se6 pentagonal pyramids, and faces with two equivalent Nb(1)Se6 pentagonal pyramids. Se(1) is bonded in a rectangular see-saw-like geometry to one Nb(2), two equivalent Nb(1), and one Cr(1) atom.
Nb3CrSe6 is Ilmenite-like structured and crystallizes in the hexagonal P6_322 space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to six equivalent Se(1) atoms to form distorted NbSe6 pentagonal pyramids that share corners with three equivalent Cr(1)Se6 octahedra, edges with three equivalent Nb(1)Se6 pentagonal pyramids, edges with three equivalent Nb(2)Se6 pentagonal pyramids, and  a faceface with one Cr(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are three shorter (2.61 Å) and three longer (2.64 Å) Nb(1)-Se(1) bond lengths. In the second Nb site, Nb(2) is bonded to six equivalent Se(1) atoms to form distorted NbSe6 pentagonal pyramids that share corners with six equivalent Cr(1)Se6 octahedra and edges with six equivalent Nb(1)Se6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 46°. All Nb(2)-Se(1) bond lengths are 2.61 Å. Cr(1) is bonded to six equivalent Se(1) atoms to form CrSe6 octahedra that share corners with six equivalent Nb(1)Se6 pentagonal pyramids, corners with six equivalent Nb(2)Se6 pentagonal pyramids, and faces with two equivalent Nb(1)Se6 pentagonal pyramids. All Cr(1)-Se(1) bond lengths are 2.56 Å. Se(1) is bonded in a rectangular see-saw-like geometry to one Nb(2), two equivalent Nb(1), and one Cr(1) atom.