FeCd3S4 is Enargite-like structured and crystallizes in the tetragonal P-4m2 space group. Fe(1) is bonded to four equivalent S(2) atoms to form FeS4 tetrahedra that share corners with four equivalent Fe(1)S4 tetrahedra and corners with eight equivalent Cd(1)S4 tetrahedra. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form CdS4 tetrahedra that share corners with four equivalent Fe(1)S4 tetrahedra, corners with four equivalent Cd(1)S4 tetrahedra, and corners with four equivalent Cd(2)S4 tetrahedra. In the second Cd site, Cd(2) is bonded to four equivalent S(1) atoms to form corner-sharing CdS4 tetrahedra. There are two inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Cd(1) and two equivalent Cd(2) atoms to form SCd4 tetrahedra that share corners with four equivalent S(2)Cd2Fe2 tetrahedra and corners with eight equivalent S(1)Cd4 tetrahedra. In the second S site, S(2) is bonded to two equivalent Fe(1) and two equivalent Cd(1) atoms to form SCd2Fe2 tetrahedra that share corners with four equivalent S(1)Cd4 tetrahedra and corners with eight equivalent S(2)Cd2Fe2 tetrahedra.
FeCd3S4 is Enargite-like structured and crystallizes in the tetragonal P-4m2 space group. Fe(1) is bonded to four equivalent S(2) atoms to form FeS4 tetrahedra that share corners with four equivalent Fe(1)S4 tetrahedra and corners with eight equivalent Cd(1)S4 tetrahedra. All Fe(1)-S(2) bond lengths are 2.36 Å. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form CdS4 tetrahedra that share corners with four equivalent Fe(1)S4 tetrahedra, corners with four equivalent Cd(1)S4 tetrahedra, and corners with four equivalent Cd(2)S4 tetrahedra. Both Cd(1)-S(1) bond lengths are 2.56 Å. Both Cd(1)-S(2) bond lengths are 2.57 Å. In the second Cd site, Cd(2) is bonded to four equivalent S(1) atoms to form corner-sharing CdS4 tetrahedra. All Cd(2)-S(1) bond lengths are 2.56 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Cd(1) and two equivalent Cd(2) atoms to form SCd4 tetrahedra that share corners with four equivalent S(2)Cd2Fe2 tetrahedra and corners with eight equivalent S(1)Cd4 tetrahedra. In the second S site, S(2) is bonded to two equivalent Fe(1) and two equivalent Cd(1) atoms to form SCd2Fe2 tetrahedra that share corners with four equivalent S(1)Cd4 tetrahedra and corners with eight equivalent S(2)Cd2Fe2 tetrahedra.