Cu(Mo3Se4)2 crystallizes in the trigonal R-3 space group. Mo(1) is bonded to one Se(1) and four equivalent Se(2) atoms to form a mixture of distorted corner and edge-sharing MoSe5 square pyramids. Cu(1) is bonded in a linear geometry to two equivalent Se(1) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 4-coordinate geometry to three equivalent Mo(1) and one Cu(1) atom. In the second Se site, Se(2) is bonded in a 4-coordinate geometry to four equivalent Mo(1) atoms.
Cu(Mo3Se4)2 crystallizes in the trigonal R-3 space group. Mo(1) is bonded to one Se(1) and four equivalent Se(2) atoms to form a mixture of distorted corner and edge-sharing MoSe5 square pyramids. The Mo(1)-Se(1) bond length is 2.56 Å. There are a spread of Mo(1)-Se(2) bond distances ranging from 2.54-2.64 Å. Cu(1) is bonded in a linear geometry to two equivalent Se(1) atoms. Both Cu(1)-Se(1) bond lengths are 2.34 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 4-coordinate geometry to three equivalent Mo(1) and one Cu(1) atom. In the second Se site, Se(2) is bonded in a 4-coordinate geometry to four equivalent Mo(1) atoms.