Cd4Te3Se is Lavarevi\'{c}ite-like structured and crystallizes in the orthorhombic Pmm2 space group. There are three inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to two equivalent Te(1) and two equivalent Se(1) atoms to form CdTe2Se2 tetrahedra that share corners with two equivalent Cd(1)Te2Se2 tetrahedra, corners with two equivalent Cd(3)Te4 tetrahedra, and corners with eight equivalent Cd(2)Te3Se tetrahedra. In the second Cd site, Cd(2) is bonded to one Te(2), two equivalent Te(1), and one Se(1) atom to form CdTe3Se tetrahedra that share corners with four equivalent Cd(1)Te2Se2 tetrahedra, corners with four equivalent Cd(2)Te3Se tetrahedra, and corners with four equivalent Cd(3)Te4 tetrahedra. In the third Cd site, Cd(3) is bonded to two equivalent Te(1) and two equivalent Te(2) atoms to form CdTe4 tetrahedra that share corners with two equivalent Cd(1)Te2Se2 tetrahedra, corners with two equivalent Cd(3)Te4 tetrahedra, and corners with eight equivalent Cd(2)Te3Se tetrahedra. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded to one Cd(1), one Cd(3), and two equivalent Cd(2) atoms to form TeCd4 tetrahedra that share corners with four equivalent Te(1)Cd4 tetrahedra, corners with four equivalent Te(2)Cd4 tetrahedra, and corners with four equivalent Se(1)Cd4 tetrahedra. In the second Te site, Te(2) is bonded to two equivalent Cd(2) and two equivalent Cd(3) atoms to form TeCd4 tetrahedra that share corners with two equivalent Te(2)Cd4 tetrahedra, corners with two equivalent Se(1)Cd4 tetrahedra, and corners with eight equivalent Te(1)Cd4 tetrahedra. Se(1) is bonded to two equivalent Cd(1) and two equivalent Cd(2) atoms to form SeCd4 tetrahedra that share corners with two equivalent Te(2)Cd4 tetrahedra, corners with two equivalent Se(1)Cd4 tetrahedra, and corners with eight equivalent Te(1)Cd4 tetrahedra.
Cd4Te3Se is Lavarevi\'{c}ite-like structured and crystallizes in the orthorhombic Pmm2 space group. There are three inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to two equivalent Te(1) and two equivalent Se(1) atoms to form CdTe2Se2 tetrahedra that share corners with two equivalent Cd(1)Te2Se2 tetrahedra, corners with two equivalent Cd(3)Te4 tetrahedra, and corners with eight equivalent Cd(2)Te3Se tetrahedra. Both Cd(1)-Te(1) bond lengths are 2.83 Å. Both Cd(1)-Se(1) bond lengths are 2.71 Å. In the second Cd site, Cd(2) is bonded to one Te(2), two equivalent Te(1), and one Se(1) atom to form CdTe3Se tetrahedra that share corners with four equivalent Cd(1)Te2Se2 tetrahedra, corners with four equivalent Cd(2)Te3Se tetrahedra, and corners with four equivalent Cd(3)Te4 tetrahedra. The Cd(2)-Te(2) bond length is 2.85 Å. Both Cd(2)-Te(1) bond lengths are 2.83 Å. The Cd(2)-Se(1) bond length is 2.68 Å. In the third Cd site, Cd(3) is bonded to two equivalent Te(1) and two equivalent Te(2) atoms to form CdTe4 tetrahedra that share corners with two equivalent Cd(1)Te2Se2 tetrahedra, corners with two equivalent Cd(3)Te4 tetrahedra, and corners with eight equivalent Cd(2)Te3Se tetrahedra. Both Cd(3)-Te(1) bond lengths are 2.82 Å. Both Cd(3)-Te(2) bond lengths are 2.83 Å. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded to one Cd(1), one Cd(3), and two equivalent Cd(2) atoms to form TeCd4 tetrahedra that share corners with four equivalent Te(1)Cd4 tetrahedra, corners with four equivalent Te(2)Cd4 tetrahedra, and corners with four equivalent Se(1)Cd4 tetrahedra. In the second Te site, Te(2) is bonded to two equivalent Cd(2) and two equivalent Cd(3) atoms to form TeCd4 tetrahedra that share corners with two equivalent Te(2)Cd4 tetrahedra, corners with two equivalent Se(1)Cd4 tetrahedra, and corners with eight equivalent Te(1)Cd4 tetrahedra. Se(1) is bonded to two equivalent Cd(1) and two equivalent Cd(2) atoms to form SeCd4 tetrahedra that share corners with two equivalent Te(2)Cd4 tetrahedra, corners with two equivalent Se(1)Cd4 tetrahedra, and corners with eight equivalent Te(1)Cd4 tetrahedra.