Cd3FeSe4 is Enargite-like structured and crystallizes in the trigonal P3m1 space group. Fe(1) is bonded to one Se(4) and three equivalent Se(1) atoms to form FeSe4 tetrahedra that share corners with three equivalent Cd(1)Se4 tetrahedra, corners with three equivalent Cd(2)Se4 tetrahedra, and corners with six equivalent Fe(1)Se4 tetrahedra. There are three inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to one Se(1) and three equivalent Se(3) atoms to form CdSe4 tetrahedra that share corners with three equivalent Fe(1)Se4 tetrahedra, corners with three equivalent Cd(3)Se4 tetrahedra, and corners with six equivalent Cd(1)Se4 tetrahedra. In the second Cd site, Cd(2) is bonded to one Se(2) and three equivalent Se(4) atoms to form CdSe4 tetrahedra that share corners with three equivalent Fe(1)Se4 tetrahedra, corners with three equivalent Cd(3)Se4 tetrahedra, and corners with six equivalent Cd(2)Se4 tetrahedra. In the third Cd site, Cd(3) is bonded to one Se(3) and three equivalent Se(2) atoms to form corner-sharing CdSe4 tetrahedra. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to three equivalent Fe(1) and one Cd(1) atom to form SeCdFe3 tetrahedra that share corners with three equivalent Se(4)Cd3Fe tetrahedra, corners with three equivalent Se(3)Cd4 tetrahedra, and corners with six equivalent Se(1)CdFe3 tetrahedra. In the second Se site, Se(2) is bonded to one Cd(2) and three equivalent Cd(3) atoms to form SeCd4 tetrahedra that share corners with three equivalent Se(4)Cd3Fe tetrahedra, corners with three equivalent Se(3)Cd4 tetrahedra, and corners with six equivalent Se(2)Cd4 tetrahedra. In the third Se site, Se(3) is bonded to one Cd(3) and three equivalent Cd(1) atoms to form SeCd4 tetrahedra that share corners with three equivalent Se(2)Cd4 tetrahedra, corners with three equivalent Se(1)CdFe3 tetrahedra, and corners with six equivalent Se(3)Cd4 tetrahedra. In the fourth Se site, Se(4) is bonded to one Fe(1) and three equivalent Cd(2) atoms to form SeCd3Fe tetrahedra that share corners with three equivalent Se(2)Cd4 tetrahedra, corners with three equivalent Se(1)CdFe3 tetrahedra, and corners with six equivalent Se(4)Cd3Fe tetrahedra.
Cd3FeSe4 is Enargite-like structured and crystallizes in the trigonal P3m1 space group. Fe(1) is bonded to one Se(4) and three equivalent Se(1) atoms to form FeSe4 tetrahedra that share corners with three equivalent Cd(1)Se4 tetrahedra, corners with three equivalent Cd(2)Se4 tetrahedra, and corners with six equivalent Fe(1)Se4 tetrahedra. The Fe(1)-Se(4) bond length is 2.47 Å. All Fe(1)-Se(1) bond lengths are 2.56 Å. There are three inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to one Se(1) and three equivalent Se(3) atoms to form CdSe4 tetrahedra that share corners with three equivalent Fe(1)Se4 tetrahedra, corners with three equivalent Cd(3)Se4 tetrahedra, and corners with six equivalent Cd(1)Se4 tetrahedra. The Cd(1)-Se(1) bond length is 2.69 Å. All Cd(1)-Se(3) bond lengths are 2.68 Å. In the second Cd site, Cd(2) is bonded to one Se(2) and three equivalent Se(4) atoms to form CdSe4 tetrahedra that share corners with three equivalent Fe(1)Se4 tetrahedra, corners with three equivalent Cd(3)Se4 tetrahedra, and corners with six equivalent Cd(2)Se4 tetrahedra. The Cd(2)-Se(2) bond length is 2.68 Å. All Cd(2)-Se(4) bond lengths are 2.68 Å. In the third Cd site, Cd(3) is bonded to one Se(3) and three equivalent Se(2) atoms to form corner-sharing CdSe4 tetrahedra. The Cd(3)-Se(3) bond length is 2.69 Å. All Cd(3)-Se(2) bond lengths are 2.67 Å. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to three equivalent Fe(1) and one Cd(1) atom to form SeCdFe3 tetrahedra that share corners with three equivalent Se(4)Cd3Fe tetrahedra, corners with three equivalent Se(3)Cd4 tetrahedra, and corners with six equivalent Se(1)CdFe3 tetrahedra. In the second Se site, Se(2) is bonded to one Cd(2) and three equivalent Cd(3) atoms to form SeCd4 tetrahedra that share corners with three equivalent Se(4)Cd3Fe tetrahedra, corners with three equivalent Se(3)Cd4 tetrahedra, and corners with six equivalent Se(2)Cd4 tetrahedra. In the third Se site, Se(3) is bonded to one Cd(3) and three equivalent Cd(1) atoms to form SeCd4 tetrahedra that share corners with three equivalent Se(2)Cd4 tetrahedra, corners with three equivalent Se(1)CdFe3 tetrahedra, and corners with six equivalent Se(3)Cd4 tetrahedra. In the fourth Se site, Se(4) is bonded to one Fe(1) and three equivalent Cd(2) atoms to form SeCd3Fe tetrahedra that share corners with three equivalent Se(2)Cd4 tetrahedra, corners with three equivalent Se(1)CdFe3 tetrahedra, and corners with six equivalent Se(4)Cd3Fe tetrahedra.