NiC5N2H3O2Cl crystallizes in the orthorhombic Pna2_1 space group. Ni(1) is bonded in a square pyramidal geometry to one N(1), one N(2), one O(1), one O(2), and one Cl(1) atom. The Ni(1)-N(1) bond length is 2.08 Å. The Ni(1)-N(2) bond length is 2.06 Å. The Ni(1)-O(1) bond length is 2.05 Å. The Ni(1)-O(2) bond length is 2.03 Å. The Ni(1)-Cl(1) bond length is 2.46 Å. There are five inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(3), one O(1), and one O(2) atom. The C(1)-C(3) bond length is 1.51 Å. The C(1)-O(1) bond length is 1.25 Å. The C(1)-O(2) bond length is 1.25 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one N(1) and one H(1) atom. The C(2)-N(1) bond length is 1.31 Å. The C(2)-H(1) bond length is 0.93 Å. In the third C site, C(3) is bonded in a distorted trigonal planar geometry to one C(1), one C(4), and one N(1) atom. The C(3)-C(4) bond length is 1.37 Å. The C(3)-N(1) bond length is 1.34 Å. In the fourth C site, C(4) is bonded in a distorted trigonal planar geometry to one C(3), one N(2), and one H(2) atom. The C(4)-N(2) bond length is 1.34 Å. The C(4)-H(2) bond length is 0.93 Å. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to one N(2) and one H(3) atom. The C(5)-N(2) bond length is 1.33 Å. The C(5)-H(3) bond length is 0.93 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to one Ni(1), one C(2), and one C(3) atom. In the second N site, N(2) is bonded in a trigonal planar geometry to one Ni(1), one C(4), and one C(5) atom. There are three inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(2) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(4) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(5) atom. There are two inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Ni(1) and one C(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Ni(1) and one C(1) atom. Cl(1) is bonded in a single-bond geometry to one Ni(1) atom. Linkers: 3 [O]C(=O)c1cnccn1. Metal clusters: 4 [Ni]. The MOF has largest included sphere 3.78 A, density 1.55 g/cm3, surface area 3667.09 m2/g, accessible volume 0.28 cm3/g