RbCN4H crystallizes in the hexagonal P6_3/m space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded to three equivalent N(1) and three equivalent N(2) atoms to form corner-sharing RbN6 octahedra. The corner-sharing octahedral tilt angles are 78°. All Rb(1)-N(1) bond lengths are 3.10 Å. All Rb(1)-N(2) bond lengths are 3.01 Å. In the second Rb site, Rb(2) is bonded to six equivalent N(1) atoms to form corner-sharing RbN6 octahedra. The corner-sharing octahedral tilt angles are 78°. All Rb(2)-N(1) bond lengths are 3.06 Å. C(1) is bonded in a trigonal planar geometry to two equivalent N(1) and one H(1) atom. Both C(1)-N(1) bond lengths are 1.34 Å. The C(1)-H(1) bond length is 1.08 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(2), one C(1), and one N(2) atom. The N(1)-N(2) bond length is 1.35 Å. In the second N site, N(2) is bonded in a trigonal planar geometry to one Rb(1), one N(1), and one N(2) atom. The N(2)-N(2) bond length is 1.32 Å. H(1) is bonded in a single-bond geometry to one C(1) atom. Linkers: 6 C1=NN=N[N]1. Metal clusters: 6 [Rb]. The MOF has largest included sphere 1.74 A, density 2.32 g/cm3, surface area 3102.40 m2/g, accessible volume 0.06 cm3/g