CdH6(CO3)2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in an octahedral geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. Both Cd(1)-O(1) bond lengths are 2.32 Å. Both Cd(1)-O(2) bond lengths are 2.30 Å. Both Cd(1)-O(4) bond lengths are 2.33 Å. In the second Cd site, Cd(2) is bonded in an octahedral geometry to two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms. Both Cd(2)-O(3) bond lengths are 2.41 Å. Both Cd(2)-O(5) bond lengths are 2.33 Å. Both Cd(2)-O(6) bond lengths are 2.28 Å. There are two inequivalent C sites. In the first C site, C(2) is bonded in a trigonal planar geometry to one H(2), one O(3), and one O(4) atom. The C(2)-H(2) bond length is 1.11 Å. The C(2)-O(3) bond length is 1.27 Å. The C(2)-O(4) bond length is 1.28 Å. In the second C site, C(1) is bonded in a trigonal planar geometry to one H(1), one O(1), and one O(2) atom. The C(1)-H(1) bond length is 1.10 Å. The C(1)-O(1) bond length is 1.27 Å. The C(1)-O(2) bond length is 1.27 Å. There are six 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 O(2) and one O(5) atom. The H(3)-O(2) bond length is 1.73 Å. The H(3)-O(5) bond length is 1.00 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(4) and one O(5) atom. The H(4)-O(4) bond length is 1.70 Å. The H(4)-O(5) bond length is 1.00 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(6) atom. The H(5)-O(6) bond length is 0.99 Å. In the sixth H site, H(6) is bonded in a distorted single-bond geometry to one O(3) and one O(6) atom. The H(6)-O(3) bond length is 1.67 Å. The H(6)-O(6) bond length is 1.00 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 1-coordinate 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(3) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Cd(2), one C(2), and one H(6) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Cd(1), one C(2), and one H(4) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to one Cd(2), one H(3), and one H(4) atom. In the sixth O site, O(6) is bonded in a distorted water-like geometry to one Cd(2), one H(5), and one H(6) atom. Linkers: 8 [O]C=O. Metal clusters: 4 [Cd]. The MOF has largest included sphere 1.77 A, density 2.47 g/cm3, surface area 3307.39 m2/g, accessible volume 0.07 cm3/g