Materials Data on Nb2CuSe4 by Materials Project

Nb2CuSe4 crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one Nb2CuSe4 sheet oriented in the (0, 0, 1) direction. there are two inequivalent Nb+3.50+ sites. In the first Nb+3.50+ site, Nb+3.50+ is bonded to six Se2- atoms to form distorted edge-sharing NbSe6 pentagonal pyramids. There are three shorter (2.62 Å) and three longer (2.65 Å) Nb–Se bond lengths. In the second Nb+3.50+ site, Nb+3.50+ is bonded to six Se2- atoms to form distorted edge-sharing NbSe6 pentagonal pyramids. There are three shorter (2.61 Å) and three longer (2.64 Å) Nb–Se bond lengths. Cu1+ is bonded in a distorted rectangular see-saw-like geometry to four Se2- atoms. There are one shorter (2.34 Å) and three longer (2.44 Å) Cu–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted T-shaped geometry to three equivalent Nb+3.50+ atoms. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Nb+3.50+ atoms. In the third Se2- site, Se2- is bonded in a 6-coordinate geometry to three equivalent Nb+3.50+ and three equivalent Cu1+ atoms. In the fourth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three equivalent Nb+3.50+ and one Cu1+ atom.