Ag2CdSnSe4 is Stannite-like structured and crystallizes in the monoclinic Pm space group. There are two inequivalent Ag sites. In the first Ag site, Ag(1) is bonded to one Se(1), one Se(3), and two equivalent Se(4) atoms to form AgSe4 tetrahedra that share corners with two equivalent Ag(1)Se4 tetrahedra, corners with two equivalent Ag(2)Se4 tetrahedra, corners with four equivalent Cd(1)Se4 tetrahedra, and corners with four equivalent Sn(1)Se4 tetrahedra. In the second Ag site, Ag(2) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form AgSe4 tetrahedra that share corners with two equivalent Ag(1)Se4 tetrahedra, corners with two equivalent Ag(2)Se4 tetrahedra, corners with four equivalent Cd(1)Se4 tetrahedra, and corners with four equivalent Sn(1)Se4 tetrahedra. Cd(1) is bonded to one Se(2), one Se(4), and two equivalent Se(3) atoms to form CdSe4 tetrahedra that share corners with two equivalent Cd(1)Se4 tetrahedra, corners with two equivalent Sn(1)Se4 tetrahedra, corners with four equivalent Ag(1)Se4 tetrahedra, and corners with four equivalent Ag(2)Se4 tetrahedra. Sn(1) is bonded to one Se(2), one Se(4), and two equivalent Se(1) atoms to form SnSe4 tetrahedra that share corners with two equivalent Cd(1)Se4 tetrahedra, corners with two equivalent Sn(1)Se4 tetrahedra, corners with four equivalent Ag(1)Se4 tetrahedra, and corners with four equivalent Ag(2)Se4 tetrahedra. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to one Ag(1), one Ag(2), and two equivalent Sn(1) atoms to form SeAg2Sn2 tetrahedra that share corners with two equivalent Se(1)Ag2Sn2 tetrahedra, corners with two equivalent Se(3)Cd2Ag2 tetrahedra, corners with four equivalent Se(2)CdAg2Sn tetrahedra, and corners with four equivalent Se(4)CdAg2Sn tetrahedra. In the second Se site, Se(2) is bonded to two equivalent Ag(2), one Cd(1), and one Sn(1) atom to form SeCdAg2Sn tetrahedra that share corners with two equivalent Se(2)CdAg2Sn tetrahedra, corners with two equivalent Se(4)CdAg2Sn tetrahedra, corners with four equivalent Se(1)Ag2Sn2 tetrahedra, and corners with four equivalent Se(3)Cd2Ag2 tetrahedra. In the third Se site, Se(3) is bonded to one Ag(1), one Ag(2), and two equivalent Cd(1) atoms to form SeCd2Ag2 tetrahedra that share corners with two equivalent Se(1)Ag2Sn2 tetrahedra, corners with two equivalent Se(3)Cd2Ag2 tetrahedra, corners with four equivalent Se(2)CdAg2Sn tetrahedra, and corners with four equivalent Se(4)CdAg2Sn tetrahedra. In the fourth Se site, Se(4) is bonded to two equivalent Ag(1), one Cd(1), and one Sn(1) atom to form SeCdAg2Sn tetrahedra that share corners with two equivalent Se(2)CdAg2Sn tetrahedra, corners with two equivalent Se(4)CdAg2Sn tetrahedra, corners with four equivalent Se(1)Ag2Sn2 tetrahedra, and corners with four equivalent Se(3)Cd2Ag2 tetrahedra.
Ag2CdSnSe4 is Stannite-like structured and crystallizes in the monoclinic Pm space group. There are two inequivalent Ag sites. In the first Ag site, Ag(1) is bonded to one Se(1), one Se(3), and two equivalent Se(4) atoms to form AgSe4 tetrahedra that share corners with two equivalent Ag(1)Se4 tetrahedra, corners with two equivalent Ag(2)Se4 tetrahedra, corners with four equivalent Cd(1)Se4 tetrahedra, and corners with four equivalent Sn(1)Se4 tetrahedra. The Ag(1)-Se(1) bond length is 2.73 Å. The Ag(1)-Se(3) bond length is 2.60 Å. Both Ag(1)-Se(4) bond lengths are 2.67 Å. In the second Ag site, Ag(2) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form AgSe4 tetrahedra that share corners with two equivalent Ag(1)Se4 tetrahedra, corners with two equivalent Ag(2)Se4 tetrahedra, corners with four equivalent Cd(1)Se4 tetrahedra, and corners with four equivalent Sn(1)Se4 tetrahedra. The Ag(2)-Se(1) bond length is 2.79 Å. The Ag(2)-Se(3) bond length is 2.63 Å. Both Ag(2)-Se(2) bond lengths are 2.69 Å. Cd(1) is bonded to one Se(2), one Se(4), and two equivalent Se(3) atoms to form CdSe4 tetrahedra that share corners with two equivalent Cd(1)Se4 tetrahedra, corners with two equivalent Sn(1)Se4 tetrahedra, corners with four equivalent Ag(1)Se4 tetrahedra, and corners with four equivalent Ag(2)Se4 tetrahedra. The Cd(1)-Se(2) bond length is 2.76 Å. The Cd(1)-Se(4) bond length is 2.72 Å. Both Cd(1)-Se(3) bond lengths are 2.62 Å. Sn(1) is bonded to one Se(2), one Se(4), and two equivalent Se(1) atoms to form SnSe4 tetrahedra that share corners with two equivalent Cd(1)Se4 tetrahedra, corners with two equivalent Sn(1)Se4 tetrahedra, corners with four equivalent Ag(1)Se4 tetrahedra, and corners with four equivalent Ag(2)Se4 tetrahedra. The Sn(1)-Se(2) bond length is 2.57 Å. The Sn(1)-Se(4) bond length is 2.58 Å. Both Sn(1)-Se(1) bond lengths are 2.73 Å. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to one Ag(1), one Ag(2), and two equivalent Sn(1) atoms to form SeAg2Sn2 tetrahedra that share corners with two equivalent Se(1)Ag2Sn2 tetrahedra, corners with two equivalent Se(3)Cd2Ag2 tetrahedra, corners with four equivalent Se(2)CdAg2Sn tetrahedra, and corners with four equivalent Se(4)CdAg2Sn tetrahedra. In the second Se site, Se(2) is bonded to two equivalent Ag(2), one Cd(1), and one Sn(1) atom to form SeCdAg2Sn tetrahedra that share corners with two equivalent Se(2)CdAg2Sn tetrahedra, corners with two equivalent Se(4)CdAg2Sn tetrahedra, corners with four equivalent Se(1)Ag2Sn2 tetrahedra, and corners with four equivalent Se(3)Cd2Ag2 tetrahedra. In the third Se site, Se(3) is bonded to one Ag(1), one Ag(2), and two equivalent Cd(1) atoms to form SeCd2Ag2 tetrahedra that share corners with two equivalent Se(1)Ag2Sn2 tetrahedra, corners with two equivalent Se(3)Cd2Ag2 tetrahedra, corners with four equivalent Se(2)CdAg2Sn tetrahedra, and corners with four equivalent Se(4)CdAg2Sn tetrahedra. In the fourth Se site, Se(4) is bonded to two equivalent Ag(1), one Cd(1), and one Sn(1) atom to form SeCdAg2Sn tetrahedra that share corners with two equivalent Se(2)CdAg2Sn tetrahedra, corners with two equivalent Se(4)CdAg2Sn tetrahedra, corners with four equivalent Se(1)Ag2Sn2 tetrahedra, and corners with four equivalent Se(3)Cd2Ag2 tetrahedra.