Cd3Pb2Se4(O6I)2 crystallizes in the monoclinic P2/c space group. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. In the second Cd site, Cd(2) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(4), one O(5), one O(6), and two equivalent O(2) atoms. Pb(1) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(4), one O(5), and three equivalent I(1) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted trigonal non-coplanar geometry to one O(1), one O(2), and one O(3) atom. In the second Se site, Se(2) is bonded in a trigonal non-coplanar geometry to one O(4), one O(5), and one O(6) atom. There are six inequivalent O sites. In the first O site, O(4) is bonded to one Cd(1), one Cd(2), one Pb(1), and one Se(2) atom to form a mixture of corner and edge-sharing OCd2PbSe tetrahedra. In the second O site, O(5) is bonded to one Cd(1), one Cd(2), one Pb(1), and one Se(2) atom to form a mixture of distorted corner and edge-sharing OCd2PbSe trigonal pyramids. In the third O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Cd(1), one Cd(2), and one Se(2) atom. In the fourth O site, O(1) is bonded in a distorted trigonal planar geometry to one Cd(1), one Cd(2), and one Se(1) atom. In the fifth O site, O(2) is bonded to two equivalent Cd(2), one Pb(1), and one Se(1) atom to form a mixture of distorted corner and edge-sharing OCd2PbSe tetrahedra. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Cd(2), one Pb(1), and one Se(1) atom. I(1) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Pb(1) atoms.
Cd3Pb2Se4(O6I)2 crystallizes in the monoclinic P2/c space group. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. Both Cd(1)-O(1) bond lengths are 2.30 Å. Both Cd(1)-O(4) bond lengths are 2.47 Å. Both Cd(1)-O(5) bond lengths are 2.48 Å. Both Cd(1)-O(6) bond lengths are 2.71 Å. In the second Cd site, Cd(2) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(4), one O(5), one O(6), and two equivalent O(2) atoms. The Cd(2)-O(1) bond length is 2.40 Å. The Cd(2)-O(3) bond length is 2.37 Å. The Cd(2)-O(4) bond length is 2.43 Å. The Cd(2)-O(5) bond length is 2.65 Å. The Cd(2)-O(6) bond length is 2.30 Å. There is one shorter (2.32 Å) and one longer (2.67 Å) Cd(2)-O(2) bond length. Pb(1) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(4), one O(5), and three equivalent I(1) atoms. The Pb(1)-O(2) bond length is 2.52 Å. The Pb(1)-O(3) bond length is 2.64 Å. The Pb(1)-O(4) bond length is 2.46 Å. The Pb(1)-O(5) bond length is 2.60 Å. There are a spread of Pb(1)-I(1) bond distances ranging from 3.47-3.54 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted trigonal non-coplanar geometry to one O(1), one O(2), and one O(3) atom. The Se(1)-O(1) bond length is 1.72 Å. The Se(1)-O(2) bond length is 1.76 Å. The Se(1)-O(3) bond length is 1.74 Å. In the second Se site, Se(2) is bonded in a trigonal non-coplanar geometry to one O(4), one O(5), and one O(6) atom. The Se(2)-O(4) bond length is 1.79 Å. The Se(2)-O(5) bond length is 1.74 Å. The Se(2)-O(6) bond length is 1.70 Å. There are six inequivalent O sites. In the first O site, O(4) is bonded to one Cd(1), one Cd(2), one Pb(1), and one Se(2) atom to form a mixture of corner and edge-sharing OCd2PbSe tetrahedra. In the second O site, O(5) is bonded to one Cd(1), one Cd(2), one Pb(1), and one Se(2) atom to form a mixture of distorted corner and edge-sharing OCd2PbSe trigonal pyramids. In the third O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Cd(1), one Cd(2), and one Se(2) atom. In the fourth O site, O(1) is bonded in a distorted trigonal planar geometry to one Cd(1), one Cd(2), and one Se(1) atom. In the fifth O site, O(2) is bonded to two equivalent Cd(2), one Pb(1), and one Se(1) atom to form a mixture of distorted corner and edge-sharing OCd2PbSe tetrahedra. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Cd(2), one Pb(1), and one Se(1) atom. I(1) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Pb(1) atoms.