NaCN5H2O3 crystallizes in the orthorhombic Ama2 space group. Na(1) is bonded in a 6-coordinate geometry to one N(2), one N(3), one N(4), one O(1), and two equivalent O(2) atoms. The Na(1)-N(2) bond length is 2.45 Å. The Na(1)-N(3) bond length is 2.48 Å. The Na(1)-N(4) bond length is 2.59 Å. The Na(1)-O(1) bond length is 2.52 Å. There is one shorter (2.45 Å) and one longer (2.49 Å) Na(1)-O(2) 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(1) and two equivalent N(2) atoms. The C(1)-N(1) bond length is 1.43 Å. Both C(1)-N(2) bond lengths are 1.34 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one N(5) and two equivalent N(4) atoms. The C(2)-N(5) bond length is 1.44 Å. Both C(2)-N(4) bond lengths are 1.34 Å. There are six inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to one C(1) and two equivalent O(1) atoms. Both N(1)-O(1) bond lengths are 1.24 Å. In the second N site, N(2) is bonded in a distorted trigonal planar geometry to one Na(1), one C(1), and one N(3) atom. The N(2)-N(3) bond length is 1.33 Å. In the third N site, N(3) is bonded in a distorted trigonal planar geometry to one Na(1), one N(2), and one N(3) atom. The N(3)-N(3) bond length is 1.35 Å. In the fourth N site, N(4) is bonded in a distorted trigonal planar geometry to one Na(1), one C(2), and one N(6) atom. The N(4)-N(6) bond length is 1.33 Å. In the fifth N site, N(5) is bonded in a trigonal planar geometry to one C(2) and two equivalent O(3) atoms. Both N(5)-O(3) bond lengths are 1.24 Å. In the sixth N site, N(6) is bonded in a 3-coordinate geometry to one N(4), one N(6), and one H(2) atom. The N(6)-N(6) bond length is 1.34 Å. The N(6)-H(2) bond length is 1.83 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(2) atom. The H(1)-O(2) bond length is 0.98 Å. In the second H site, H(2) is bonded in a single-bond geometry to one N(6) and one O(2) atom. The H(2)-O(2) bond length is 1.00 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Na(1) and one N(1) atom. In the second O site, O(2) is bonded in a distorted water-like geometry to two equivalent Na(1), one H(1), and one H(2) atom. In the third O site, O(3) is bonded in a single-bond geometry to one N(5) atom. Linkers: 3 O=[N+]([O-])C1=NN=N[N]1 ,1 O=[N+]([O-])C1=N[N]N=N1. Metal clusters: 4 [Na]. The MOF has largest included sphere 3.02 A, density 1.64 g/cm3, surface area 3046.30 m2/g, accessible volume 0.16 cm3/g