CdC6H4(N2Se)2 crystallizes in the monoclinic C2/c space group. There are three inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in an octahedral geometry to one N(3), one N(4), one N(5), one N(7), one Se(1), and one Se(2) atom. The Cd(1)-N(3) bond length is 2.34 Å. The Cd(1)-N(4) bond length is 2.37 Å. The Cd(1)-N(5) bond length is 2.44 Å. The Cd(1)-N(7) bond length is 2.43 Å. The Cd(1)-Se(1) bond length is 2.81 Å. The Cd(1)-Se(2) bond length is 2.78 Å. In the second Cd site, Cd(2) is bonded in an octahedral geometry to two equivalent N(6), two equivalent Se(3), and two equivalent Se(4) atoms. Both Cd(2)-N(6) bond lengths are 2.54 Å. Both Cd(2)-Se(3) bond lengths are 2.84 Å. Both Cd(2)-Se(4) bond lengths are 2.83 Å. In the third Cd site, Cd(3) is bonded in an octahedral geometry to two equivalent N(1), two equivalent N(2), and two equivalent N(8) atoms. Both Cd(3)-N(1) bond lengths are 2.34 Å. Both Cd(3)-N(2) bond lengths are 2.32 Å. Both Cd(3)-N(8) bond lengths are 2.39 Å. There are twelve inequivalent C sites. In the first C site, C(1) is bonded in a distorted single-bond geometry to one N(1) and one Se(1) atom. The C(1)-N(1) bond length is 1.18 Å. The C(1)-Se(1) bond length is 1.81 Å. In the second C site, C(2) is bonded in a single-bond geometry to one N(2) and one Se(2) atom. The C(2)-N(2) bond length is 1.18 Å. The C(2)-Se(2) bond length is 1.80 Å. In the third C site, C(3) is bonded in a distorted single-bond geometry to one N(3) and one Se(3) atom. The C(3)-N(3) bond length is 1.18 Å. The C(3)-Se(3) bond length is 1.80 Å. In the fourth C site, C(4) is bonded in a single-bond geometry to one N(4) and one Se(4) atom. The C(4)-N(4) bond length is 1.18 Å. The C(4)-Se(4) bond length is 1.80 Å. In the fifth C site, C(5) is bonded in a trigonal planar geometry to one N(5), one N(6), and one H(1) atom. The C(5)-N(5) bond length is 1.34 Å. The C(5)-N(6) bond length is 1.34 Å. The C(5)-H(1) bond length is 1.09 Å. In the sixth C site, C(6) is bonded in a distorted trigonal planar geometry to one C(7), one N(6), and one H(2) atom. The C(6)-C(7) bond length is 1.39 Å. The C(6)-N(6) bond length is 1.35 Å. The C(6)-H(2) bond length is 1.09 Å. In the seventh C site, C(7) is bonded in a distorted single-bond geometry to one C(6), one C(8), and one H(3) atom. The C(7)-C(8) bond length is 1.39 Å. The C(7)-H(3) bond length is 1.09 Å. In the eighth C site, C(8) is bonded in a distorted trigonal planar geometry to one C(7), one N(5), and one H(4) atom. The C(8)-N(5) bond length is 1.35 Å. The C(8)-H(4) bond length is 1.09 Å. In the ninth C site, C(9) is bonded in a trigonal planar geometry to one N(7), one N(8), and one H(5) atom. The C(9)-N(7) bond length is 1.34 Å. The C(9)-N(8) bond length is 1.34 Å. The C(9)-H(5) bond length is 1.09 Å. In the tenth C site, C(10) is bonded in a distorted trigonal planar geometry to one C(11), one N(8), and one H(6) atom. The C(10)-C(11) bond length is 1.39 Å. The C(10)-N(8) bond length is 1.34 Å. The C(10)-H(6) bond length is 1.09 Å. In the eleventh C site, C(11) is bonded in a distorted single-bond geometry to one C(10), one C(12), and one H(7) atom. The C(11)-C(12) bond length is 1.39 Å. The C(11)-H(7) bond length is 1.09 Å. In the twelfth C site, C(12) is bonded in a distorted trigonal planar geometry to one C(11), one N(7), and one H(8) atom. The C(12)-N(7) bond length is 1.35 Å. The C(12)-H(8) bond length is 1.09 Å. There are eight inequivalent N sites. In the first N site, N(1) is bonded in a linear geometry to one Cd(3) and one C(1) atom. In the second N site, N(2) is bonded in a distorted bent 150 degrees geometry to one Cd(3) and one C(2) atom. In the third N site, N(3) is bonded in a linear geometry to one Cd(1) and one C(3) atom. In the fourth N site, N(4) is bonded in a bent 150 degrees geometry to one Cd(1) and one C(4) atom. In the fifth N site, N(5) is bonded in a trigonal planar geometry to one Cd(1), one C(5), and one C(8) atom. In the sixth N site, N(6) is bonded in a trigonal planar geometry to one Cd(2), one C(5), and one C(6) atom. In the seventh N site, N(7) is bonded in a trigonal planar geometry to one Cd(1), one C(12), and one C(9) atom. In the eighth N site, N(8) is bonded in a trigonal planar geometry to one Cd(3), one C(10), and one C(9) atom. There are eight inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(5) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(6) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(7) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(8) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(9) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one C(10) atom. In the seventh H site, H(7) is bonded in a single-bond geometry to one C(11) atom. In the eighth H site, H(8) is bonded in a single-bond geometry to one C(12) atom. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in an L-shaped geometry to one Cd(1) and one C(1) atom. In the second Se site, Se(2) is bonded in an L-shaped geometry to one Cd(1) and one C(2) atom. In the third Se site, Se(3) is bonded in a water-like geometry to one Cd(2) and one C(3) atom. In the fourth Se site, Se(4) is bonded in an L-shaped geometry to one Cd(2) and one C(4) atom. Linkers: 7 c1cncnc1. Metal clusters: 8 [Cd]. The MOF has largest included sphere 2.69 A, density 2.53 g/cm3, surface area 2969.02 m2/g, accessible volume 0.13 cm3/g