Li2SnSe3 is Enargite-like structured and crystallizes in the monoclinic Cc space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form LiSe4 tetrahedra that share corners with two equivalent Li(1)Se4 tetrahedra, corners with five equivalent Li(2)Se4 tetrahedra, and corners with five equivalent Sn(1)Se4 tetrahedra. In the second Li site, Li(2) is bonded to one Se(1), one Se(2), and two equivalent Se(3) atoms to form LiSe4 tetrahedra that share corners with two equivalent Li(2)Se4 tetrahedra, corners with five equivalent Li(1)Se4 tetrahedra, and corners with five equivalent Sn(1)Se4 tetrahedra. Sn(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form SnSe4 tetrahedra that share corners with two equivalent Sn(1)Se4 tetrahedra, corners with five equivalent Li(1)Se4 tetrahedra, and corners with five equivalent Li(2)Se4 tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Li(1), one Li(2), and two equivalent Sn(1) atoms to form SeLi2Sn2 tetrahedra that share corners with two equivalent Se(1)Li2Sn2 tetrahedra, corners with five equivalent Se(2)Li3Sn tetrahedra, and corners with five equivalent Se(3)Li3Sn tetrahedra. In the second Se site, Se(2) is bonded to one Li(2), two equivalent Li(1), and one Sn(1) atom to form SeLi3Sn tetrahedra that share corners with two equivalent Se(2)Li3Sn tetrahedra, corners with five equivalent Se(1)Li2Sn2 tetrahedra, and corners with five equivalent Se(3)Li3Sn tetrahedra. In the third Se site, Se(3) is bonded to one Li(1), two equivalent Li(2), and one Sn(1) atom to form SeLi3Sn tetrahedra that share corners with two equivalent Se(3)Li3Sn tetrahedra, corners with five equivalent Se(1)Li2Sn2 tetrahedra, and corners with five equivalent Se(2)Li3Sn tetrahedra.
Li2SnSe3 is Enargite-like structured and crystallizes in the monoclinic Cc space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form LiSe4 tetrahedra that share corners with two equivalent Li(1)Se4 tetrahedra, corners with five equivalent Li(2)Se4 tetrahedra, and corners with five equivalent Sn(1)Se4 tetrahedra. The Li(1)-Se(1) bond length is 2.71 Å. The Li(1)-Se(3) bond length is 2.55 Å. There is one shorter (2.52 Å) and one longer (2.55 Å) Li(1)-Se(2) bond length. In the second Li site, Li(2) is bonded to one Se(1), one Se(2), and two equivalent Se(3) atoms to form LiSe4 tetrahedra that share corners with two equivalent Li(2)Se4 tetrahedra, corners with five equivalent Li(1)Se4 tetrahedra, and corners with five equivalent Sn(1)Se4 tetrahedra. The Li(2)-Se(1) bond length is 2.66 Å. The Li(2)-Se(2) bond length is 2.50 Å. There is one shorter (2.50 Å) and one longer (2.53 Å) Li(2)-Se(3) bond length. Sn(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form SnSe4 tetrahedra that share corners with two equivalent Sn(1)Se4 tetrahedra, corners with five equivalent Li(1)Se4 tetrahedra, and corners with five equivalent Li(2)Se4 tetrahedra. The Sn(1)-Se(2) bond length is 2.49 Å. The Sn(1)-Se(3) bond length is 2.48 Å. There is one shorter (2.62 Å) and one longer (2.63 Å) Sn(1)-Se(1) bond length. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Li(1), one Li(2), and two equivalent Sn(1) atoms to form SeLi2Sn2 tetrahedra that share corners with two equivalent Se(1)Li2Sn2 tetrahedra, corners with five equivalent Se(2)Li3Sn tetrahedra, and corners with five equivalent Se(3)Li3Sn tetrahedra. In the second Se site, Se(2) is bonded to one Li(2), two equivalent Li(1), and one Sn(1) atom to form SeLi3Sn tetrahedra that share corners with two equivalent Se(2)Li3Sn tetrahedra, corners with five equivalent Se(1)Li2Sn2 tetrahedra, and corners with five equivalent Se(3)Li3Sn tetrahedra. In the third Se site, Se(3) is bonded to one Li(1), two equivalent Li(2), and one Sn(1) atom to form SeLi3Sn tetrahedra that share corners with two equivalent Se(3)Li3Sn tetrahedra, corners with five equivalent Se(1)Li2Sn2 tetrahedra, and corners with five equivalent Se(2)Li3Sn tetrahedra.