RbCN4H2O crystallizes in the monoclinic P2_1/c space group. Rb(1) is bonded in a 10-coordinate geometry to one N(2), two equivalent N(3), two equivalent N(4), one H(1), one H(2), and three equivalent O(1) atoms. The Rb(1)-N(2) bond length is 3.24 Å. There is one shorter (3.09 Å) and one longer (3.10 Å) Rb(1)-N(3) bond length. There is one shorter (3.03 Å) and one longer (3.17 Å) Rb(1)-N(4) bond length. The Rb(1)-H(1) bond length is 3.06 Å. The Rb(1)-H(2) bond length is 2.86 Å. There are a spread of Rb(1)-O(1) bond distances ranging from 2.93-3.04 Å. C(1) is bonded in a distorted trigonal planar geometry to one C(1), one N(2), and one N(4) atom. The C(1)-C(1) bond length is 1.45 Å. The C(1)-N(2) bond length is 1.35 Å. The C(1)-N(4) bond length is 1.35 Å. There are four inequivalent N sites. In the first N site, N(1) is bonded in a 3-coordinate geometry to one N(3), one N(4), and one H(1) atom. The N(1)-N(3) bond length is 1.32 Å. The N(1)-N(4) bond length is 1.34 Å. The N(1)-H(1) bond length is 1.80 Å. In the second N site, N(2) is bonded in a distorted single-bond geometry to one Rb(1), one C(1), and one N(3) atom. The N(2)-N(3) bond length is 1.34 Å. In the third N site, N(3) is bonded to two equivalent Rb(1), one N(1), and one N(2) atom to form distorted corner-sharing NRb2N2 tetrahedra. In the fourth N site, N(4) is bonded in a distorted single-bond geometry to two equivalent Rb(1), one C(1), and one N(1) atom. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one Rb(1), one N(1), and one O(1) atom. The H(1)-O(1) bond length is 1.00 Å. In the second H site, H(2) is bonded in a single-bond geometry to one Rb(1) and one O(1) atom. The H(2)-O(1) bond length is 1.00 Å. O(1) is bonded in a water-like geometry to three equivalent Rb(1), one H(1), and one H(2) atom. Linkers: 1 [N]1N=NN=C1C1=NN=N[N]1. Metal clusters: 4 [Rb]. The MOF has largest included sphere 1.38 A, density 2.46 g/cm3, surface area 2571.08 m2/g, accessible volume 0.08 cm3/g