KHC2O4 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), two equivalent O(3), and three equivalent O(4) atoms. The K(1)-O(1) bond length is 2.96 Å. The K(1)-O(2) bond length is 2.73 Å. Both K(1)-O(3) bond lengths are 2.80 Å. There are a spread of K(1)-O(4) bond distances ranging from 2.79-2.83 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(3) atom. The C(1)-O(1) bond length is 1.32 Å. The C(1)-O(3) bond length is 1.23 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one O(2) and one O(4) atom. The C(2)-O(2) bond length is 1.27 Å. The C(2)-O(4) bond length is 1.25 Å. H(1) is bonded in a linear geometry to one O(1) and one O(2) atom. The H(1)-O(1) bond length is 1.08 Å. The H(1)-O(2) bond length is 1.42 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to one K(1), one C(1), and one H(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one K(1), one C(2), and one H(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent K(1) and one C(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to three equivalent K(1) and one C(2) atom. Linkers: 4 [O]C(=O)C(=O)O. Metal clusters: 4 [K]. The MOF has largest included sphere 0.95 A, density 2.05 g/cm3, surface area 766.12 m2/g, accessible volume 0.00 cm3/g