NaCN4H3O crystallizes in the orthorhombic Pmma space group. Na(1) is bonded to four equivalent N(2) and two equivalent O(1) atoms to form face-sharing NaN4O2 octahedra. All Na(1)-N(2) bond lengths are 2.54 Å. Both Na(1)-O(1) bond lengths are 2.39 Å. C(1) is bonded in a trigonal planar geometry to two equivalent N(2) and one H(1) atom. Both C(1)-N(2) bond lengths are 1.34 Å. The C(1)-H(1) bond length is 1.09 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded in a 3-coordinate geometry to one N(1), one N(2), and one H(2) atom. The N(1)-N(1) bond length is 1.31 Å. The N(1)-N(2) bond length is 1.35 Å. The N(1)-H(2) bond length is 1.83 Å. In the second N site, N(2) is bonded to two equivalent Na(1), one C(1), and one N(1) atom to form a mixture of distorted edge and corner-sharing NNa2CN tetrahedra. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one N(1) and one O(1) atom. The H(2)-O(1) bond length is 0.99 Å. O(1) is bonded in a distorted water-like geometry to two equivalent Na(1) and two equivalent H(2) atoms. Linkers: 2 C1=NN=N[N]1. Metal clusters: 2 [Na]. The MOF has largest included sphere 1.16 A, density 1.76 g/cm3, surface area 2928.29 m2/g, accessible volume 0.09 cm3/g