KC2N7H4O crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 8-coordinate geometry to one N(3), one N(4), one N(6), two equivalent N(2), one H(4), and two equivalent O(1) atoms. The K(1)-N(3) bond length is 3.08 Å. The K(1)-N(4) bond length is 2.97 Å. The K(1)-N(6) bond length is 2.91 Å. There is one shorter (2.84 Å) and one longer (2.85 Å) K(1)-N(2) bond length. The K(1)-H(4) bond length is 2.81 Å. There is one shorter (2.65 Å) and one longer (2.74 Å) K(1)-O(1) bond length. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one N(2), one N(3), and one N(5) atom. The C(1)-N(2) bond length is 1.32 Å. The C(1)-N(3) bond length is 1.38 Å. The C(1)-N(5) bond length is 1.39 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one N(1), one N(5), and one N(7) atom. The C(2)-N(1) bond length is 1.34 Å. The C(2)-N(5) bond length is 1.37 Å. The C(2)-N(7) bond length is 1.35 Å. There are seven inequivalent N sites. In the first N site, N(3) is bonded in a distorted single-bond geometry to one K(1) and one C(1) atom. In the second N site, N(4) is bonded in a distorted single-bond geometry to one K(1) and one O(1) atom. The N(4)-O(1) bond length is 1.29 Å. In the third N site, N(5) is bonded in a distorted trigonal planar geometry to one C(1), one C(2), and one N(6) atom. The N(5)-N(6) bond length is 1.40 Å. In the fourth N site, N(6) is bonded in a water-like geometry to one K(1), one N(5), one H(1), and one H(2) atom. The N(6)-H(1) bond length is 1.03 Å. The N(6)-H(2) bond length is 1.03 Å. In the fifth N site, N(7) is bonded in a distorted trigonal planar geometry to one C(2), one H(3), and one H(4) atom. The N(7)-H(3) bond length is 1.03 Å. The N(7)-H(4) bond length is 1.03 Å. In the sixth N site, N(1) is bonded in a distorted single-bond geometry to one C(2) and one N(2) atom. The N(1)-N(2) bond length is 1.40 Å. In the seventh N site, N(2) is bonded in a distorted single-bond geometry to two equivalent K(1), one C(1), and one N(1) atom. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one N(6) atom. In the second H site, H(2) is bonded in a single-bond geometry to one N(6) atom. In the third H site, H(3) is bonded in a single-bond geometry to one N(7) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one K(1) and one N(7) atom. O(1) is bonded in a 3-coordinate geometry to two equivalent K(1) and one N(4) atom. Linkers: 4 Nc1nnc([N][N][O])n1N. Metal clusters: 4 [K]. The MOF has largest included sphere 1.27 A, density 1.91 g/cm3, surface area 2112.61 m2/g, accessible volume 0.03 cm3/g