Cd6C21N31H21 crystallizes in the monoclinic C2/c space group. There are four inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in an octahedral geometry to one N(1), one N(13), one N(2), one N(3), one N(5), and one N(8) atom. The Cd(1)-N(1) bond length is 2.32 Å. The Cd(1)-N(13) bond length is 2.32 Å. The Cd(1)-N(2) bond length is 2.37 Å. The Cd(1)-N(3) bond length is 2.32 Å. The Cd(1)-N(5) bond length is 2.35 Å. The Cd(1)-N(8) bond length is 2.34 Å. In the second Cd site, Cd(2) is bonded in a rectangular see-saw-like geometry to one N(12), one N(14), one N(4), and one N(9) atom. The Cd(2)-N(12) bond length is 2.28 Å. The Cd(2)-N(14) bond length is 2.37 Å. The Cd(2)-N(4) bond length is 2.21 Å. The Cd(2)-N(9) bond length is 2.21 Å. In the third Cd site, Cd(3) is bonded in a T-shaped geometry to one N(16) and two equivalent N(6) atoms. The Cd(3)-N(16) bond length is 2.26 Å. Both Cd(3)-N(6) bond lengths are 2.20 Å. In the fourth Cd site, Cd(4) is bonded in an octahedral geometry to two equivalent N(10), two equivalent N(11), and two equivalent N(7) atoms. Both Cd(4)-N(10) bond lengths are 2.34 Å. Both Cd(4)-N(11) bond lengths are 2.33 Å. Both Cd(4)-N(7) bond lengths are 2.32 Å. There are eleven inequivalent C sites. In the first C site, C(11) is bonded in a trigonal planar geometry to two equivalent N(14) and one H(11) atom. Both C(11)-N(14) bond lengths are 1.27 Å. The C(11)-H(11) bond length is 0.95 Å. In the second C site, C(1) is bonded in a trigonal planar geometry to one N(1), one N(16), and one H(1) atom. The C(1)-N(1) bond length is 1.33 Å. The C(1)-N(16) bond length is 1.34 Å. The C(1)-H(1) bond length is 0.95 Å. In the third C site, C(2) is bonded in a trigonal planar geometry to one N(3), one N(4), and one H(2) atom. The C(2)-N(3) bond length is 1.31 Å. The C(2)-N(4) bond length is 1.35 Å. The C(2)-H(2) bond length is 0.95 Å. In the fourth C site, C(3) is bonded in a trigonal planar geometry to one N(2), one N(4), and one H(3) atom. The C(3)-N(2) bond length is 1.31 Å. The C(3)-N(4) bond length is 1.35 Å. The C(3)-H(3) bond length is 0.95 Å. In the fifth C site, C(4) is bonded in a trigonal planar geometry to one N(5), one N(6), and one H(4) atom. The C(4)-N(5) bond length is 1.31 Å. The C(4)-N(6) bond length is 1.35 Å. The C(4)-H(4) bond length is 0.95 Å. In the sixth C site, C(5) is bonded in a trigonal planar geometry to one N(6), one N(7), and one H(5) atom. The C(5)-N(6) bond length is 1.36 Å. The C(5)-N(7) bond length is 1.32 Å. The C(5)-H(5) bond length is 0.95 Å. In the seventh C site, C(6) is bonded in a trigonal planar geometry to one N(8), one N(9), and one H(6) atom. The C(6)-N(8) bond length is 1.32 Å. The C(6)-N(9) bond length is 1.35 Å. The C(6)-H(6) bond length is 0.95 Å. In the eighth C site, C(7) is bonded in a trigonal planar geometry to one N(10), one N(9), and one H(7) atom. The C(7)-N(10) bond length is 1.32 Å. The C(7)-N(9) bond length is 1.35 Å. The C(7)-H(7) bond length is 0.95 Å. In the ninth C site, C(8) is bonded in a trigonal planar geometry to one N(11), one N(12), and one H(8) atom. The C(8)-N(11) bond length is 1.31 Å. The C(8)-N(12) bond length is 1.33 Å. The C(8)-H(8) bond length is 0.95 Å. In the tenth C site, C(9) is bonded in a trigonal planar geometry to one N(12), one N(13), and one H(9) atom. The C(9)-N(12) bond length is 1.34 Å. The C(9)-N(13) bond length is 1.32 Å. The C(9)-H(9) bond length is 0.95 Å. In the eleventh C site, C(10) is bonded in a trigonal planar geometry to one N(14), one N(15), and one H(10) atom. The C(10)-N(14) bond length is 1.35 Å. The C(10)-N(15) bond length is 1.31 Å. The C(10)-H(10) bond length is 0.95 Å. There are sixteen inequivalent N sites. In the first N site, N(1) is bonded in a distorted trigonal planar geometry to one Cd(1), one C(1), and one N(1) atom. The N(1)-N(1) bond length is 1.36 Å. In the second N site, N(2) is bonded in a 3-coordinate geometry to one Cd(1), one C(3), and one N(3) atom. The N(2)-N(3) bond length is 1.37 Å. In the third N site, N(3) is bonded in a 3-coordinate geometry to one Cd(1), one C(2), and one N(2) atom. In the fourth N site, N(4) is bonded in a distorted trigonal planar geometry to one Cd(2), one C(2), and one C(3) atom. In the fifth N site, N(5) is bonded in a 3-coordinate geometry to one Cd(1), one C(4), and one N(7) atom. The N(5)-N(7) bond length is 1.37 Å. In the sixth N site, N(6) is bonded in a trigonal planar geometry to one Cd(3), one C(4), and one C(5) atom. In the seventh N site, N(7) is bonded in a 3-coordinate geometry to one Cd(4), one C(5), and one N(5) atom. In the eighth N site, N(8) is bonded in a 3-coordinate geometry to one Cd(1), one C(6), and one N(10) atom. The N(8)-N(10) bond length is 1.37 Å. In the ninth N site, N(9) is bonded in a distorted trigonal planar geometry to one Cd(2), one C(6), and one C(7) atom. In the tenth N site, N(10) is bonded in a 3-coordinate geometry to one Cd(4), one C(7), and one N(8) atom. In the eleventh N site, N(11) is bonded in a 3-coordinate geometry to one Cd(4), one C(8), and one N(13) atom. The N(11)-N(13) bond length is 1.35 Å. In the twelfth N site, N(12) is bonded in a distorted trigonal planar geometry to one Cd(2), one C(8), and one C(9) atom. In the thirteenth N site, N(13) is bonded in a distorted trigonal planar geometry to one Cd(1), one C(9), and one N(11) atom. In the fourteenth N site, N(14) is bonded in a 2-coordinate geometry to one Cd(2), one C(10), and one C(11) atom. In the fifteenth N site, N(15) is bonded in a single-bond geometry to one C(10) atom. In the sixteenth N site, N(16) is bonded in a trigonal planar geometry to one Cd(3) and two equivalent C(1) atoms. There are eleven inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(2) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(3) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(4) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(5) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one C(6) atom. In the seventh H site, H(7) is bonded in a single-bond geometry to one C(7) atom. In the eighth H site, H(8) is bonded in a single-bond geometry to one C(8) atom. In the ninth H site, H(9) is bonded in a single-bond geometry to one C(9) atom. In the tenth H site, H(10) is bonded in a single-bond geometry to one C(10) atom. In the eleventh H site, H(11) is bonded in a single-bond geometry to one C(11) atom. Linkers: 4 C1=NC=N[N]1 ,6 C1=NN=C[N]1 ,2 [N]1=CN=NC=1 ,2 c1nncn1[Cd](n1cnnc1)n1cnnc1. Metal clusters: 10 [Cd]. The MOF has largest included sphere 4.52 A, density 1.94 g/cm3, surface area 3009.64 m2/g, accessible volume 0.22 cm3/g