SmCuSe2 crystallizes in the monoclinic P2_1/c space group. Sm(1) is bonded in a 7-coordinate geometry to three equivalent Se(2) and four equivalent Se(1) atoms. Cu(1) is bonded to one Se(1) and three equivalent Se(2) atoms to form a mixture of distorted corner and edge-sharing CuSe4 tetrahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to four equivalent Sm(1) and one Cu(1) atom to form a mixture of distorted corner and edge-sharing SeSm4Cu trigonal bipyramids. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to three equivalent Sm(1) and three equivalent Cu(1) atoms.
SmCuSe2 crystallizes in the monoclinic P2_1/c space group. Sm(1) is bonded in a 7-coordinate geometry to three equivalent Se(2) and four equivalent Se(1) atoms. There are a spread of Sm(1)-Se(2) bond distances ranging from 2.95-3.21 Å. There are a spread of Sm(1)-Se(1) bond distances ranging from 2.91-2.99 Å. Cu(1) is bonded to one Se(1) and three equivalent Se(2) atoms to form a mixture of distorted corner and edge-sharing CuSe4 tetrahedra. The Cu(1)-Se(1) bond length is 2.44 Å. There are a spread of Cu(1)-Se(2) bond distances ranging from 2.44-2.60 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to four equivalent Sm(1) and one Cu(1) atom to form a mixture of distorted corner and edge-sharing SeSm4Cu trigonal bipyramids. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to three equivalent Sm(1) and three equivalent Cu(1) atoms.