Materials Data on Nb2CuTe4 by Materials Project
Nb2CuTe4 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are two inequivalent Nb+3.50+ sites. In the first Nb+3.50+ site, Nb+3.50+ is bonded to six Te2- atoms to form distorted NbTe6 octahedra that share corners with three equivalent CuTe4 tetrahedra, edges with six NbTe6 octahedra, and a faceface with one CuTe4 tetrahedra. There are a spread of Nb–Te bond distances ranging from 2.78–3.00 Å. In the second Nb+3.50+ site, Nb+3.50+ is bonded to six Te2- atoms to form distorted NbTe6 octahedra that share corners with six equivalent CuTe4 tetrahedra and edges with six NbTe6 octahedra. There are a spread of Nb–Te bond distances ranging from 2.75–2.96 Å. Cu1+ is bonded to four Te2- atoms to form CuTe4 tetrahedra that share corners with nine NbTe6 octahedra, corners with two equivalent CuTe4 tetrahedra, and a faceface with one NbTe6 octahedra. The corner-sharing octahedra tilt angles range from 49–63°. There are a spread of Cu–Te bond distances ranging from 2.58–2.62 Å. There are four inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 4-coordinate geometry to three Nb+3.50+ and one Cu1+ atom. In the second Te2- site, Te2- is bonded in a 3-coordinate geometry to three Nb+3.50+ atoms. In the third Te2- site, Te2- is bonded to three Nb+3.50+ and one Cu1+ atom to form distorted corner-sharing TeNb3Cu tetrahedra. In the fourth Te2- site, Te2- is bonded in a 5-coordinate geometry to three Nb+3.50+ and two equivalent Cu1+ atoms.