CuISe3 crystallizes in the trigonal R-3m space group. Cu(1) is bonded to one Se(2), one Se(3), and two equivalent I(1) atoms to form edge-sharing CuSe2I2 tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a water-like geometry to two equivalent Se(3) atoms. In the second Se site, Se(2) is bonded in a distorted single-bond geometry to one Cu(1) and two equivalent Se(2) atoms. In the third Se site, Se(3) is bonded in a distorted single-bond geometry to one Cu(1) and two equivalent Se(1) atoms. I(1) is bonded in a distorted L-shaped geometry to two equivalent Cu(1) atoms.
CuISe3 crystallizes in the trigonal R-3m space group. Cu(1) is bonded to one Se(2), one Se(3), and two equivalent I(1) atoms to form edge-sharing CuSe2I2 tetrahedra. The Cu(1)-Se(2) bond length is 2.41 Å. The Cu(1)-Se(3) bond length is 2.42 Å. Both Cu(1)-I(1) bond lengths are 2.68 Å. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a water-like geometry to two equivalent Se(3) atoms. Both Se(1)-Se(3) bond lengths are 2.40 Å. In the second Se site, Se(2) is bonded in a distorted single-bond geometry to one Cu(1) and two equivalent Se(2) atoms. Both Se(2)-Se(2) bond lengths are 2.44 Å. In the third Se site, Se(3) is bonded in a distorted single-bond geometry to one Cu(1) and two equivalent Se(1) atoms. I(1) is bonded in a distorted L-shaped geometry to two equivalent Cu(1) atoms.