Materials Data on Nb3Tl2Br9 by Materials Project
Nb3Tl2Br9 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Nb+2.33+ sites. In the first Nb+2.33+ site, Nb+2.33+ is bonded to five Br1- atoms to form corner-sharing NbBr5 square pyramids. There are four shorter (2.62 Å) and one longer (2.85 Å) Nb–Br bond lengths. In the second Nb+2.33+ site, Nb+2.33+ is bonded to five Br1- atoms to form distorted corner-sharing NbBr5 square pyramids. There are a spread of Nb–Br bond distances ranging from 2.61–2.89 Å. Tl1+ is bonded in a 4-coordinate geometry to ten Br1- atoms. There are a spread of Tl–Br bond distances ranging from 3.27–4.18 Å. There are six inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 3-coordinate geometry to two Nb+2.33+ and one Tl1+ atom. In the second Br1- site, Br1- is bonded in a distorted trigonal planar geometry to one Nb+2.33+ and two equivalent Tl1+ atoms. In the third Br1- site, Br1- is bonded in a 2-coordinate geometry to two equivalent Nb+2.33+ and four equivalent Tl1+ atoms. In the fourth Br1- site, Br1- is bonded in a 2-coordinate geometry to two equivalent Nb+2.33+ and two equivalent Tl1+ atoms. In the fifth Br1- site, Br1- is bonded in a 2-coordinate geometry to two Nb+2.33+ and two equivalent Tl1+ atoms. In the sixth Br1- site, Br1- is bonded to one Nb+2.33+ and three equivalent Tl1+ atoms to form a mixture of distorted edge and corner-sharing BrNbTl3 tetrahedra.