LiSmSe2 is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. Li(1) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form LiSe6 octahedra that share corners with six equivalent Li(1)Se6 octahedra, edges with four equivalent Li(1)Se6 octahedra, and edges with eight equivalent Sm(1)Se6 octahedra. The corner-sharing octahedra are not tilted. Sm(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form SmSe6 octahedra that share corners with six equivalent Sm(1)Se6 octahedra, edges with four equivalent Sm(1)Se6 octahedra, and edges with eight equivalent Li(1)Se6 octahedra. The corner-sharing octahedra are not tilted. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Li(1) and four equivalent Sm(1) atoms to form SeLi2Sm4 octahedra that share corners with six equivalent Se(1)Li2Sm4 octahedra, edges with four equivalent Se(1)Li2Sm4 octahedra, and edges with eight equivalent Se(2)Li4Sm2 octahedra. The corner-sharing octahedra are not tilted. In the second Se site, Se(2) is bonded to four equivalent Li(1) and two equivalent Sm(1) atoms to form SeLi4Sm2 octahedra that share corners with six equivalent Se(2)Li4Sm2 octahedra, edges with four equivalent Se(2)Li4Sm2 octahedra, and edges with eight equivalent Se(1)Li2Sm4 octahedra. The corner-sharing octahedra are not tilted.
LiSmSe2 is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. Li(1) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form LiSe6 octahedra that share corners with six equivalent Li(1)Se6 octahedra, edges with four equivalent Li(1)Se6 octahedra, and edges with eight equivalent Sm(1)Se6 octahedra. The corner-sharing octahedra are not tilted. Both Li(1)-Se(1) bond lengths are 2.84 Å. All Li(1)-Se(2) bond lengths are 2.95 Å. Sm(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form SmSe6 octahedra that share corners with six equivalent Sm(1)Se6 octahedra, edges with four equivalent Sm(1)Se6 octahedra, and edges with eight equivalent Li(1)Se6 octahedra. The corner-sharing octahedra are not tilted. Both Sm(1)-Se(2) bond lengths are 2.84 Å. All Sm(1)-Se(1) bond lengths are 2.95 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Li(1) and four equivalent Sm(1) atoms to form SeLi2Sm4 octahedra that share corners with six equivalent Se(1)Li2Sm4 octahedra, edges with four equivalent Se(1)Li2Sm4 octahedra, and edges with eight equivalent Se(2)Li4Sm2 octahedra. The corner-sharing octahedra are not tilted. In the second Se site, Se(2) is bonded to four equivalent Li(1) and two equivalent Sm(1) atoms to form SeLi4Sm2 octahedra that share corners with six equivalent Se(2)Li4Sm2 octahedra, edges with four equivalent Se(2)Li4Sm2 octahedra, and edges with eight equivalent Se(1)Li2Sm4 octahedra. The corner-sharing octahedra are not tilted.