Materials Data on NbCuSe2 by Materials Project
NbCuSe2 is Ilmenite-like structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Nb3+ is bonded to six Se2- atoms to form distorted NbSe6 pentagonal pyramids that share corners with nine equivalent CuSe4 trigonal pyramids, edges with six equivalent NbSe6 pentagonal pyramids, and a faceface with one CuSe4 trigonal pyramid. There are three shorter (2.63 Å) and three longer (2.67 Å) Nb–Se bond lengths. Cu1+ is bonded to four Se2- atoms to form distorted CuSe4 trigonal pyramids that share corners with nine equivalent NbSe6 pentagonal pyramids, corners with six equivalent CuSe4 trigonal pyramids, and a faceface with one NbSe6 pentagonal pyramid. There are one shorter (2.35 Å) and three longer (2.44 Å) Cu–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to three equivalent Nb3+ and three equivalent Cu1+ atoms. In the second Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to three equivalent Nb3+ and one Cu1+ atom.