KC3H(NO)4 crystallizes in the triclinic P-1 space group. K(1) is bonded in a 8-coordinate geometry to one N(1), one N(2), one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms. The K(1)-N(1) bond length is 2.83 Å. The K(1)-N(2) bond length is 2.93 Å. The K(1)-O(2) bond length is 2.91 Å. The K(1)-O(4) bond length is 2.97 Å. There is one shorter (2.96 Å) and one longer (3.12 Å) K(1)-O(1) bond length. There is one shorter (2.86 Å) and one longer (2.97 Å) K(1)-O(3) bond length. There are three inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one N(1), one N(2), and one N(3) atom. The C(1)-N(1) bond length is 1.34 Å. The C(1)-N(2) bond length is 1.36 Å. The C(1)-N(3) bond length is 1.43 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one C(3), one N(1), and one N(4) atom. The C(2)-C(3) bond length is 1.42 Å. The C(2)-N(1) bond length is 1.35 Å. The C(2)-N(4) bond length is 1.42 Å. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one C(2), one N(2), and one H(1) atom. The C(3)-N(2) bond length is 1.34 Å. The C(3)-H(1) bond length is 1.09 Å. There are four inequivalent N sites. In the first N site, N(1) is bonded in a distorted water-like geometry to one K(1), one C(1), and one C(2) atom. In the second N site, N(2) is bonded in a distorted water-like geometry to one K(1), one C(1), and one C(3) atom. In the third N site, N(3) is bonded in a trigonal planar geometry to one C(1), one O(3), and one O(4) atom. The N(3)-O(3) bond length is 1.25 Å. The N(3)-O(4) bond length is 1.25 Å. In the fourth N site, N(4) is bonded in a trigonal planar geometry to one C(2), one O(1), and one O(2) atom. The N(4)-O(1) bond length is 1.26 Å. The N(4)-O(2) bond length is 1.25 Å. H(1) is bonded in a single-bond geometry to one C(3) atom. There are four 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 N(4) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(1) and one N(4) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent K(1) and one N(3) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one K(1) and one N(3) atom. Linkers: 2 O=[N+]([O-])[C]1C=NC([N+](=O)[O-])=N1. Metal clusters: 2 [K]. The MOF has largest included sphere 1.41 A, density 1.96 g/cm3, surface area 0.00 m2/g, accessible volume 0.00 cm3/g