K2Cd3H20(C5O6)4 crystallizes in the orthorhombic Ibam space group. K(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. Both K(1)-O(2) bond lengths are 2.92 Å. Both K(1)-O(5) bond lengths are 2.75 Å. Both K(1)-O(6) bond lengths are 3.13 Å. Both K(1)-O(7) bond lengths are 2.77 Å. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. All Cd(1)-O(1) bond lengths are 2.70 Å. All Cd(1)-O(2) bond lengths are 2.30 Å. In the second Cd site, Cd(2) is bonded in a distorted pentagonal pyramidal geometry to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms. Both Cd(2)-O(1) bond lengths are 2.45 Å. Both Cd(2)-O(3) bond lengths are 2.35 Å. Both Cd(2)-O(4) bond lengths are 2.26 Å. There are six inequivalent C sites. In the first C site, C(5) is bonded in a trigonal planar geometry to one C(2), one C(4), and one C(6) atom. The C(5)-C(2) bond length is 1.50 Å. The C(5)-C(4) bond length is 1.41 Å. The C(5)-C(6) bond length is 1.40 Å. In the second C site, C(6) is bonded in a distorted single-bond geometry to two equivalent C(5) and one H(7) atom. The C(6)-H(7) bond length is 1.09 Å. In the third C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(4), one O(1), and one O(2) atom. The C(1)-C(4) bond length is 1.50 Å. The C(1)-O(1) bond length is 1.28 Å. The C(1)-O(2) bond length is 1.27 Å. In the fourth C site, C(2) is bonded in a distorted bent 120 degrees geometry to one C(5), one O(3), and one O(4) atom. The C(2)-O(3) bond length is 1.28 Å. The C(2)-O(4) bond length is 1.28 Å. In the fifth C site, C(3) is bonded in a distorted single-bond geometry to two equivalent C(4) and one H(6) atom. Both C(3)-C(4) bond lengths are 1.40 Å. The C(3)-H(6) bond length is 1.09 Å. In the sixth C site, C(4) is bonded in a trigonal planar geometry to one C(1), one C(3), and one C(5) atom. There are seven inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(5) atom. The H(1)-O(5) bond length is 0.99 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(5) atom. The H(2)-O(5) bond length is 0.97 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(6) atom. The H(3)-O(6) bond length is 0.98 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(6) atom. The H(4)-O(6) bond length is 0.98 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(7) atom. The H(5)-O(7) bond length is 0.98 Å. In the sixth H site, H(6) is bonded in a single-bond geometry to one C(3) atom. In the seventh H site, H(7) is bonded in a single-bond geometry to one C(6) atom. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Cd(1), one Cd(2), and one C(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(1), one Cd(1), and one C(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Cd(2) and one C(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Cd(2) and one C(2) atom. In the fifth O site, O(5) is bonded in a water-like geometry to two equivalent K(1), one H(1), and one H(2) atom. In the sixth O site, O(6) is bonded in a water-like geometry to one K(1), one H(3), and one H(4) atom. In the seventh O site, O(7) is bonded in a water-like geometry to two equivalent K(1) and two equivalent H(5) atoms. Linkers: 4 [O]C(=O)c1cc(C([O])=O)c(C([O])=O)cc1C([O])=O. Metal clusters: 4 [K] ,6 [Cd]. The MOF has largest included sphere 1.52 A, density 2.37 g/cm3, surface area 2329.23 m2/g, accessible volume 0.05 cm3/g