NiC5N3H4 crystallizes in the monoclinic P2_1/c space group. Ni(1) is bonded in a distorted tetrahedral geometry to one C(5), one N(1), one N(2), and one N(3) atom. The Ni(1)-C(5) bond length is 1.86 Å. The Ni(1)-N(1) bond length is 2.00 Å. The Ni(1)-N(2) bond length is 1.99 Å. The Ni(1)-N(3) bond length is 1.91 Å. There are five inequivalent C sites. In the first C site, C(4) is bonded in a distorted trigonal planar geometry to one C(3), one N(2), and one H(4) atom. The C(4)-C(3) bond length is 1.38 Å. The C(4)-N(2) bond length is 1.35 Å. The C(4)-H(4) bond length is 1.09 Å. In the second C site, C(5) is bonded in a linear geometry to one Ni(1) and one N(3) atom. The C(5)-N(3) bond length is 1.18 Å. In the third C site, C(1) is bonded in a distorted trigonal planar geometry to one C(2), one N(1), and one H(2) atom. The C(1)-C(2) bond length is 1.38 Å. The C(1)-N(1) bond length is 1.35 Å. The C(1)-H(2) bond length is 1.09 Å. In the fourth C site, C(2) is bonded in a distorted bent 120 degrees geometry to one C(1), one N(1), and one H(3) atom. The C(2)-N(1) bond length is 1.35 Å. The C(2)-H(3) bond length is 1.09 Å. In the fifth C site, C(3) is bonded in a distorted bent 120 degrees geometry to one C(4), one N(2), and one H(1) atom. The C(3)-N(2) bond length is 1.36 Å. The C(3)-H(1) bond length is 1.09 Å. There are three inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to one Ni(1), one C(1), and one C(2) atom. In the second N site, N(2) is bonded in a trigonal planar geometry to one Ni(1), one C(3), and one C(4) atom. In the third N site, N(3) is bonded in a linear geometry to one Ni(1) and one C(5) atom. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(3) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(1) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(2) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(4) atom. Linkers: 2 c1cnccn1. Metal clusters: 4 [Ni]. The MOF has largest included sphere 2.10 A, density 1.93 g/cm3, surface area 3727.83 m2/g, accessible volume 0.09 cm3/g