FeH2(C3N4)2 crystallizes in the cubic Pm-3m space group. Fe(1) is bonded in a square co-planar geometry to four equivalent N(1) atoms. All Fe(1)-N(1) bond lengths are 2.13 Å. There are three inequivalent C sites. In the first C site, C(1) is bonded in a single-bond geometry to two equivalent C(3) and one H(1) atom. Both C(1)-C(3) bond lengths are 1.39 Å. The C(1)-H(1) bond length is 0.95 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one C(3) and two equivalent N(2) atoms. The C(2)-C(3) bond length is 1.46 Å. Both C(2)-N(2) bond lengths are 1.33 Å. In the third C site, C(3) is bonded in a trigonal planar geometry to one C(2) and two equivalent C(1) atoms. There are two inequivalent N sites. In the first N site, N(1) is bonded in a distorted trigonal planar geometry to one Fe(1), one N(1), and one N(2) atom. The N(1)-N(1) bond length is 1.32 Å. The N(1)-N(2) bond length is 1.34 Å. In the second N site, N(2) is bonded in a water-like geometry to one C(2) and one N(1) atom. H(1) is bonded in a single-bond geometry to one C(1) atom. Linkers: 8 c1c(C2=NN=N[N]2)cc(C2=NN=N[N]2)cc1C1=NN=N[N]1. Metal clusters: 3 N1=N[Fe]23=NN=[Fe]14N=N[Fe]1(=NN=[Fe](N=N2)(N=N1)N=N3)N=N4. The MOF has largest included sphere 15.66 A, density 0.72 g/cm3, surface area 3693.51 m2/g, accessible volume 1.01 cm3/g