CsCN5H2 crystallizes in the orthorhombic Pnma space group. Cs(1) is bonded in a 9-coordinate geometry to one N(3), four equivalent N(1), and four equivalent N(2) atoms. The Cs(1)-N(3) bond length is 3.44 Å. There are two shorter (3.23 Å) and two longer (3.24 Å) Cs(1)-N(1) bond lengths. There are two shorter (3.33 Å) and two longer (3.41 Å) Cs(1)-N(2) bond lengths. C(1) is bonded in a trigonal planar geometry to one N(3) and two equivalent N(1) atoms. The C(1)-N(3) bond length is 1.37 Å. Both C(1)-N(1) bond lengths are 1.35 Å. There are three inequivalent N sites. In the first N site, N(3) is bonded in a distorted trigonal non-coplanar geometry to one Cs(1), one C(1), and two equivalent H(1) atoms. Both N(3)-H(1) bond lengths are 1.02 Å. In the second N site, N(1) is bonded in a distorted single-bond geometry to two equivalent Cs(1), one C(1), and one N(2) atom. The N(1)-N(2) bond length is 1.36 Å. In the third N site, N(2) is bonded in a distorted water-like geometry to two equivalent Cs(1), one N(1), and one N(2) atom. The N(2)-N(2) bond length is 1.31 Å. H(1) is bonded in a single-bond geometry to one N(3) atom. Linkers: 4 NC1=NN=N[N]1. Metal clusters: 4 [Cs]. The MOF has largest included sphere 1.60 A, density 2.84 g/cm3, surface area 2683.91 m2/g, accessible volume 0.08 cm3/g