EuCd3S4 is Enargite-like structured and crystallizes in the trigonal R3m space group. Eu(1) is bonded to one S(4) and three equivalent S(3) atoms to form EuS4 tetrahedra that share corners with three equivalent Cd(1)S4 tetrahedra, corners with three equivalent Cd(3)S4 tetrahedra, and corners with six equivalent Eu(1)S4 tetrahedra. There are three inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to one S(1) and three equivalent S(4) atoms to form CdS4 tetrahedra that share corners with three equivalent Eu(1)S4 tetrahedra, corners with three equivalent Cd(2)S4 tetrahedra, and corners with six equivalent Cd(1)S4 tetrahedra. In the second Cd site, Cd(2) is bonded to one S(2) and three equivalent S(1) atoms to form corner-sharing CdS4 tetrahedra. In the third Cd site, Cd(3) is bonded to one S(3) and three equivalent S(2) atoms to form CdS4 tetrahedra that share corners with three equivalent Eu(1)S4 tetrahedra, corners with three equivalent Cd(2)S4 tetrahedra, and corners with six equivalent Cd(3)S4 tetrahedra. There are four inequivalent S sites. In the first S site, S(1) is bonded to one Cd(1) and three equivalent Cd(2) atoms to form SCd4 tetrahedra that share corners with three equivalent S(2)Cd4 tetrahedra, corners with three equivalent S(4)EuCd3 tetrahedra, and corners with six equivalent S(1)Cd4 tetrahedra. In the second S site, S(2) is bonded to one Cd(2) and three equivalent Cd(3) atoms to form SCd4 tetrahedra that share corners with three equivalent S(1)Cd4 tetrahedra, corners with three equivalent S(3)Eu3Cd tetrahedra, and corners with six equivalent S(2)Cd4 tetrahedra. In the third S site, S(3) is bonded to three equivalent Eu(1) and one Cd(3) atom to form SEu3Cd tetrahedra that share corners with three equivalent S(2)Cd4 tetrahedra, corners with three equivalent S(4)EuCd3 tetrahedra, and corners with six equivalent S(3)Eu3Cd tetrahedra. In the fourth S site, S(4) is bonded to one Eu(1) and three equivalent Cd(1) atoms to form SEuCd3 tetrahedra that share corners with three equivalent S(1)Cd4 tetrahedra, corners with three equivalent S(3)Eu3Cd tetrahedra, and corners with six equivalent S(4)EuCd3 tetrahedra.
EuCd3S4 is Enargite-like structured and crystallizes in the trigonal R3m space group. Eu(1) is bonded to one S(4) and three equivalent S(3) atoms to form EuS4 tetrahedra that share corners with three equivalent Cd(1)S4 tetrahedra, corners with three equivalent Cd(3)S4 tetrahedra, and corners with six equivalent Eu(1)S4 tetrahedra. The Eu(1)-S(4) bond length is 2.80 Å. All Eu(1)-S(3) bond lengths are 2.74 Å. There are three inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to one S(1) and three equivalent S(4) atoms to form CdS4 tetrahedra that share corners with three equivalent Eu(1)S4 tetrahedra, corners with three equivalent Cd(2)S4 tetrahedra, and corners with six equivalent Cd(1)S4 tetrahedra. The Cd(1)-S(1) bond length is 2.56 Å. All Cd(1)-S(4) bond lengths are 2.62 Å. In the second Cd site, Cd(2) is bonded to one S(2) and three equivalent S(1) atoms to form corner-sharing CdS4 tetrahedra. The Cd(2)-S(2) bond length is 2.58 Å. All Cd(2)-S(1) bond lengths are 2.61 Å. In the third Cd site, Cd(3) is bonded to one S(3) and three equivalent S(2) atoms to form CdS4 tetrahedra that share corners with three equivalent Eu(1)S4 tetrahedra, corners with three equivalent Cd(2)S4 tetrahedra, and corners with six equivalent Cd(3)S4 tetrahedra. The Cd(3)-S(3) bond length is 2.59 Å. All Cd(3)-S(2) bond lengths are 2.61 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded to one Cd(1) and three equivalent Cd(2) atoms to form SCd4 tetrahedra that share corners with three equivalent S(2)Cd4 tetrahedra, corners with three equivalent S(4)EuCd3 tetrahedra, and corners with six equivalent S(1)Cd4 tetrahedra. In the second S site, S(2) is bonded to one Cd(2) and three equivalent Cd(3) atoms to form SCd4 tetrahedra that share corners with three equivalent S(1)Cd4 tetrahedra, corners with three equivalent S(3)Eu3Cd tetrahedra, and corners with six equivalent S(2)Cd4 tetrahedra. In the third S site, S(3) is bonded to three equivalent Eu(1) and one Cd(3) atom to form SEu3Cd tetrahedra that share corners with three equivalent S(2)Cd4 tetrahedra, corners with three equivalent S(4)EuCd3 tetrahedra, and corners with six equivalent S(3)Eu3Cd tetrahedra. In the fourth S site, S(4) is bonded to one Eu(1) and three equivalent Cd(1) atoms to form SEuCd3 tetrahedra that share corners with three equivalent S(1)Cd4 tetrahedra, corners with three equivalent S(3)Eu3Cd tetrahedra, and corners with six equivalent S(4)EuCd3 tetrahedra.