Materials Data on CuSe3I by Materials Project
CuISe3 crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three CuISe3 sheets oriented in the (0, 0, 1) direction. Cu1+ is bonded to two Se and two equivalent I1- atoms to form edge-sharing CuSe2I2 tetrahedra. There are one shorter (2.41 Å) and one longer (2.42 Å) Cu–Se bond lengths. Both Cu–I bond lengths are 2.68 Å. There are three inequivalent Se sites. In the first Se site, Se is bonded in a distorted square co-planar geometry to two equivalent Se and two equivalent I1- atoms. Both Se–Se bond lengths are 2.40 Å. Both Se–I bond lengths are 3.63 Å. In the second Se site, Se is bonded in a distorted single-bond geometry to one Cu1+ atom. In the third Se site, Se is bonded in a distorted single-bond geometry to one Cu1+ and two equivalent Se atoms. I1- is bonded in a 2-coordinate geometry to two equivalent Cu1+ and two equivalent Se atoms.