CdH6(C2O3)2 crystallizes in the monoclinic C2/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(2), two equivalent O(3), and two equivalent O(4) atoms. Both Cd(1)-O(1) bond lengths are 2.50 Å. Both Cd(1)-O(2) bond lengths are 2.38 Å. Both Cd(1)-O(3) bond lengths are 2.37 Å. Both Cd(1)-O(4) bond lengths are 2.62 Å. In the second Cd site, Cd(2) is bonded in a distorted octahedral geometry to one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. The Cd(2)-O(4) bond length is 2.33 Å. The Cd(2)-O(5) bond length is 2.35 Å. The Cd(2)-O(6) bond length is 2.32 Å. The Cd(2)-O(7) bond length is 2.34 Å. The Cd(2)-O(8) bond length is 2.33 Å. The Cd(2)-O(9) bond length is 2.42 Å. There are six inequivalent C sites. In the first C site, C(1) is bonded in a bent 120 degrees geometry to one C(2), one O(1), and one O(2) atom. The C(1)-C(2) bond length is 1.50 Å. The C(1)-O(1) bond length is 1.27 Å. The C(1)-O(2) bond length is 1.29 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one C(1), one C(4), and one C(6) atom. The C(2)-C(4) bond length is 1.50 Å. The C(2)-C(6) bond length is 1.35 Å. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one O(3) and one O(4) atom. The C(3)-O(3) bond length is 1.29 Å. The C(3)-O(4) bond length is 1.27 Å. In the fourth C site, C(4) is bonded in a distorted water-like geometry to one C(2), one H(7), and one H(8) atom. The C(4)-H(7) bond length is 1.10 Å. The C(4)-H(8) bond length is 1.10 Å. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to one O(5) and one O(8) atom. The C(5)-O(5) bond length is 1.28 Å. The C(5)-O(8) bond length is 1.26 Å. In the sixth C site, C(6) is bonded in a distorted single-bond geometry to one C(2) and one H(9) atom. The C(6)-H(9) bond length is 1.09 Å. There are nine inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(6) atom. The H(1)-O(6) bond length is 0.99 Å. In the second H site, H(2) is bonded in a distorted linear geometry to one O(2) and one O(6) atom. The H(2)-O(2) bond length is 1.66 Å. The H(2)-O(6) bond length is 1.00 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(7) atom. The H(3)-O(7) bond length is 0.99 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(7) atom. The H(4)-O(7) bond length is 0.99 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(9) atom. The H(5)-O(9) bond length is 0.99 Å. In the sixth H site, H(6) is bonded in a single-bond geometry to one O(5) and one O(9) atom. The H(6)-O(5) bond length is 1.71 Å. The H(6)-O(9) bond length is 1.00 Å. In the seventh H site, H(7) is bonded in a single-bond geometry to one C(4) atom. In the eighth H site, H(8) is bonded in a single-bond geometry to one C(4) atom. In the ninth H site, H(9) is bonded in a single-bond geometry to one C(6) atom. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Cd(1) and one C(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Cd(1), one C(1), and one H(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Cd(1) and one C(3) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Cd(1), one Cd(2), and one C(3) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Cd(2), one C(5), and one H(6) atom. In the sixth O site, O(6) is bonded in a distorted water-like geometry to one Cd(2), one H(1), and one H(2) atom. In the seventh O site, O(7) is bonded in a distorted water-like geometry to one Cd(2), one H(3), and one H(4) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one Cd(2) and one C(5) atom. In the ninth O site, O(9) is bonded in a water-like geometry to one Cd(2), one H(5), and one H(6) atom. Linkers: 4 [O]C(=O)/C=C(\CC([O])=O)C([O])=O. Metal clusters: 6 [Cd]. The MOF has largest included sphere 2.51 A, density 2.57 g/cm3, surface area 2840.10 m2/g, accessible volume 0.05 cm3/g