KC3N2H5O5 crystallizes in the orthorhombic Pnnm space group. K(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. Both K(1)-O(1) bond lengths are 2.73 Å. Both K(1)-O(3) bond lengths are 2.76 Å. Both K(1)-O(4) bond lengths are 2.98 Å. Both K(1)-O(5) bond lengths are 2.83 Å. There are three inequivalent C sites. In the first C site, C(3) is bonded in a trigonal planar geometry to one N(1), one N(2), and one O(4) atom. The C(3)-N(1) bond length is 1.42 Å. The C(3)-N(2) bond length is 1.33 Å. The C(3)-O(4) bond length is 1.25 Å. In the second C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(2) atom. The C(1)-O(1) bond length is 1.26 Å. The C(1)-O(2) bond length is 1.26 Å. In the third C site, C(2) is bonded in a distorted bent 120 degrees geometry to one N(1) and one O(3) atom. The C(2)-N(1) bond length is 1.36 Å. The C(2)-O(3) bond length is 1.24 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to one C(2), one C(3), and one H(1) atom. The N(1)-H(1) bond length is 1.04 Å. In the second N site, N(2) is bonded in a trigonal planar geometry to one C(3), one H(2), and one H(3) atom. The N(2)-H(2) bond length is 1.03 Å. The N(2)-H(3) bond length is 1.02 Å. There are five inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one N(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one N(2) atom. In the third H site, H(3) is bonded in a single-bond geometry to one N(2) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(5) atom. The H(4)-O(5) bond length is 0.99 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(5) atom. The H(5)-O(5) bond length is 0.98 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent K(1) and one C(1) atom. In the second O site, O(5) is bonded in a water-like geometry to two equivalent K(1), one H(4), and one H(5) atom. In the third O site, O(2) is bonded in a distorted single-bond geometry to one C(1) atom. In the fourth O site, O(3) is bonded in a distorted single-bond geometry to two equivalent K(1) and one C(2) atom. In the fifth O site, O(4) is bonded in a single-bond geometry to two equivalent K(1) and one C(3) atom. Linkers: 3 NC(=O)NC(=O)C([O])=O. Metal clusters: 4 [K]. The MOF has largest included sphere 1.79 A, density 1.85 g/cm3, surface area 2359.26 m2/g, accessible volume 0.03 cm3/g