K2C3H(NO)3 crystallizes in the orthorhombic Cmcm space group. K(1) is bonded in a 8-coordinate geometry to two equivalent N(2), two equivalent O(2), and four equivalent O(1) atoms. Both K(1)-N(2) bond lengths are 3.04 Å. Both K(1)-O(2) bond lengths are 2.92 Å. There are two shorter (2.78 Å) and two longer (2.91 Å) K(1)-O(1) bond lengths. There are two 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 O(1) atom. The C(1)-N(1) bond length is 1.38 Å. The C(1)-N(2) bond length is 1.35 Å. The C(1)-O(1) bond length is 1.27 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to two equivalent N(2) and one O(2) atom. Both C(2)-N(2) bond lengths are 1.37 Å. The C(2)-O(2) bond length is 1.29 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to two equivalent C(1) and one H(1) atom. The N(1)-H(1) bond length is 1.03 Å. In the second N site, N(2) is bonded in a bent 120 degrees geometry to two equivalent K(1), one C(1), and one C(2) atom. H(1) is bonded in a distorted single-bond geometry to one N(1) atom. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to four equivalent K(1) and one C(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to four equivalent K(1) and one C(2) atom. Linkers: 1 O=C1[N]C(=O)NC(=O)[N]1. Metal clusters: 4 [K]. The MOF has largest included sphere 0.84 A, density 2.27 g/cm3, surface area 0.00 m2/g, accessible volume 0.00 cm3/g