Cu3(BiI4)4 crystallizes in the monoclinic Cm space group. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one I(1), one I(7), and two equivalent I(10) atoms to form CuI4 tetrahedra that share  a cornercorner with one Bi(2)I6 octahedra and corners with two equivalent Cu(3)BiI4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. In the second Cu site, Cu(2) is bonded to one I(11), one I(12), and two equivalent I(8) atoms to form CuI4 tetrahedra that share corners with four equivalent Bi(3)I6 octahedra and  a cornercorner with one Cu(3)BiI4 tetrahedra. The corner-sharing octahedral tilt angles range from 54-61°. In the third Cu site, Cu(3) is bonded to one Bi(1), one I(12), one I(6), and two equivalent I(10) atoms to form distorted corner-sharing CuBiI4 tetrahedra. There are three inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 7-coordinate geometry to one Cu(3), one I(6), one I(7), two equivalent I(10), and two equivalent I(3) atoms. In the second Bi site, Bi(2) is bonded to one I(1), one I(9), two equivalent I(3), and two equivalent I(4) atoms to form BiI6 octahedra that share  a cornercorner with one Cu(1)I4 tetrahedra and edges with two equivalent Bi(3)I6 octahedra. In the third Bi site, Bi(3) is bonded to one I(11), one I(2), one I(4), one I(5), one I(8), and one I(9) atom to form BiI6 octahedra that share corners with two equivalent Cu(2)I4 tetrahedra,  an edgeedge with one Bi(2)I6 octahedra, and edges with two equivalent Bi(3)I6 octahedra. There are twelve inequivalent I sites. In the first I site, I(1) is bonded in a bent 120 degrees geometry to one Cu(1) and one Bi(2) atom. In the second I site, I(2) is bonded in an L-shaped geometry to two equivalent Bi(3) atoms. In the third I site, I(3) is bonded in an L-shaped geometry to one Bi(1) and one Bi(2) atom. In the fourth I site, I(4) is bonded in an L-shaped geometry to one Bi(2) and one Bi(3) atom. In the fifth I site, I(5) is bonded in an L-shaped geometry to two equivalent Bi(3) atoms. In the sixth I site, I(6) is bonded in a 2-coordinate geometry to one Cu(3) and one Bi(1) atom. In the seventh I site, I(7) is bonded in a bent 120 degrees geometry to one Cu(1) and one Bi(1) atom. In the eighth I site, I(8) is bonded in a bent 120 degrees geometry to one Cu(2) and one Bi(3) atom. In the ninth I site, I(9) is bonded in a distorted T-shaped geometry to one Bi(2) and two equivalent Bi(3) atoms. In the tenth I site, I(10) is bonded in a 3-coordinate geometry to one Cu(1), one Cu(3), and one Bi(1) atom. In the eleventh I site, I(11) is bonded in a distorted trigonal planar geometry to one Cu(2) and two equivalent Bi(3) atoms. In the twelfth I site, I(12) is bonded in a water-like geometry to one Cu(2) and one Cu(3) atom.
Cu3(BiI4)4 crystallizes in the monoclinic Cm space group. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one I(1), one I(7), and two equivalent I(10) atoms to form CuI4 tetrahedra that share  a cornercorner with one Bi(2)I6 octahedra and corners with two equivalent Cu(3)BiI4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. The Cu(1)-I(1) bond length is 2.66 Å. The Cu(1)-I(7) bond length is 2.57 Å. Both Cu(1)-I(10) bond lengths are 2.66 Å. In the second Cu site, Cu(2) is bonded to one I(11), one I(12), and two equivalent I(8) atoms to form CuI4 tetrahedra that share corners with four equivalent Bi(3)I6 octahedra and  a cornercorner with one Cu(3)BiI4 tetrahedra. The corner-sharing octahedral tilt angles range from 54-61°. The Cu(2)-I(11) bond length is 2.94 Å. The Cu(2)-I(12) bond length is 2.52 Å. Both Cu(2)-I(8) bond lengths are 2.58 Å. In the third Cu site, Cu(3) is bonded to one Bi(1), one I(12), one I(6), and two equivalent I(10) atoms to form distorted corner-sharing CuBiI4 tetrahedra. The Cu(3)-Bi(1) bond length is 3.15 Å. The Cu(3)-I(12) bond length is 2.55 Å. The Cu(3)-I(6) bond length is 2.66 Å. Both Cu(3)-I(10) bond lengths are 2.67 Å. There are three inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 7-coordinate geometry to one Cu(3), one I(6), one I(7), two equivalent I(10), and two equivalent I(3) atoms. The Bi(1)-I(6) bond length is 3.03 Å. The Bi(1)-I(7) bond length is 3.16 Å. Both Bi(1)-I(10) bond lengths are 3.25 Å. Both Bi(1)-I(3) bond lengths are 3.06 Å. In the second Bi site, Bi(2) is bonded to one I(1), one I(9), two equivalent I(3), and two equivalent I(4) atoms to form BiI6 octahedra that share  a cornercorner with one Cu(1)I4 tetrahedra and edges with two equivalent Bi(3)I6 octahedra. The Bi(2)-I(1) bond length is 2.95 Å. The Bi(2)-I(9) bond length is 3.40 Å. Both Bi(2)-I(3) bond lengths are 3.13 Å. Both Bi(2)-I(4) bond lengths are 3.07 Å. In the third Bi site, Bi(3) is bonded to one I(11), one I(2), one I(4), one I(5), one I(8), and one I(9) atom to form BiI6 octahedra that share corners with two equivalent Cu(2)I4 tetrahedra,  an edgeedge with one Bi(2)I6 octahedra, and edges with two equivalent Bi(3)I6 octahedra. The Bi(3)-I(11) bond length is 3.18 Å. The Bi(3)-I(2) bond length is 3.08 Å. The Bi(3)-I(4) bond length is 3.18 Å. The Bi(3)-I(5) bond length is 3.06 Å. The Bi(3)-I(8) bond length is 3.04 Å. The Bi(3)-I(9) bond length is 3.17 Å. There are twelve inequivalent I sites. In the first I site, I(1) is bonded in a bent 120 degrees geometry to one Cu(1) and one Bi(2) atom. In the second I site, I(2) is bonded in an L-shaped geometry to two equivalent Bi(3) atoms. In the third I site, I(3) is bonded in an L-shaped geometry to one Bi(1) and one Bi(2) atom. In the fourth I site, I(4) is bonded in an L-shaped geometry to one Bi(2) and one Bi(3) atom. In the fifth I site, I(5) is bonded in an L-shaped geometry to two equivalent Bi(3) atoms. In the sixth I site, I(6) is bonded in a 2-coordinate geometry to one Cu(3) and one Bi(1) atom. In the seventh I site, I(7) is bonded in a bent 120 degrees geometry to one Cu(1) and one Bi(1) atom. In the eighth I site, I(8) is bonded in a bent 120 degrees geometry to one Cu(2) and one Bi(3) atom. In the ninth I site, I(9) is bonded in a distorted T-shaped geometry to one Bi(2) and two equivalent Bi(3) atoms. In the tenth I site, I(10) is bonded in a 3-coordinate geometry to one Cu(1), one Cu(3), and one Bi(1) atom. In the eleventh I site, I(11) is bonded in a distorted trigonal planar geometry to one Cu(2) and two equivalent Bi(3) atoms. In the twelfth I site, I(12) is bonded in a water-like geometry to one Cu(2) and one Cu(3) atom.