NiC7NH5O5 crystallizes in the monoclinic P2_1/c space group. Ni(1) is bonded in an octahedral geometry to one N(1), one O(1), one O(2), one O(3), one O(4), and one O(5) atom. The Ni(1)-N(1) bond length is 2.02 Å. The Ni(1)-O(1) bond length is 2.22 Å. The Ni(1)-O(2) bond length is 2.02 Å. The Ni(1)-O(3) bond length is 2.17 Å. The Ni(1)-O(4) bond length is 2.18 Å. The Ni(1)-O(5) bond length is 2.11 Å. There are seven inequivalent C sites. In the first C site, C(1) is bonded in a distorted trigonal planar geometry to one C(2), one N(1), and one H(3) atom. The C(1)-C(2) bond length is 1.40 Å. The C(1)-N(1) bond length is 1.35 Å. The C(1)-H(3) bond length is 1.09 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one C(1), one C(3), and one C(6) atom. The C(2)-C(3) bond length is 1.40 Å. The C(2)-C(6) bond length is 1.50 Å. In the third C site, C(3) is bonded in a distorted single-bond geometry to one C(2), one C(4), and one H(4) atom. The C(3)-C(4) bond length is 1.40 Å. The C(3)-H(4) bond length is 1.09 Å. In the fourth C site, C(4) is bonded in a trigonal planar geometry to one C(3), one C(5), and one C(7) atom. The C(4)-C(5) bond length is 1.40 Å. The C(4)-C(7) bond length is 1.49 Å. In the fifth C site, C(5) is bonded in a distorted trigonal planar geometry to one C(4), one N(1), and one H(5) atom. The C(5)-N(1) bond length is 1.35 Å. The C(5)-H(5) bond length is 1.09 Å. In the sixth C site, C(6) is bonded in a distorted bent 120 degrees geometry to one C(2), one O(1), and one O(2) atom. The C(6)-O(1) bond length is 1.28 Å. The C(6)-O(2) bond length is 1.27 Å. In the seventh C site, C(7) is bonded in a distorted bent 120 degrees geometry to one C(4), one O(3), and one O(4) atom. The C(7)-O(3) bond length is 1.28 Å. The C(7)-O(4) bond length is 1.27 Å. N(1) is bonded in a trigonal planar geometry to one Ni(1), one C(1), and one C(5) atom. There are five inequivalent H sites. In the first H site, H(1) is bonded in a distorted linear geometry to one O(3) and one O(5) atom. The H(1)-O(3) bond length is 1.63 Å. The H(1)-O(5) bond length is 1.00 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(5) atom. The H(2)-O(5) bond length is 0.99 Å. In the third H site, H(3) is bonded in a single-bond geometry to one C(1) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(3) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(5) atom. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Ni(1) and one C(6) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Ni(1) and one C(6) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ni(1), one C(7), and one H(1) atom. In the fourth O site, O(4) is bonded in a distorted L-shaped geometry to one Ni(1) and one C(7) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to one Ni(1), one H(1), and one H(2) atom. Linkers: 4 [O]C(=O)c1cncc(C([O])=O)c1. Metal clusters: 2 O.O.[C]1O[Ni]2(O1)O[C]O[Ni]1(O[C]O1)O[C]O2. RCSR code: sql. The MOF has largest included sphere 1.67 A, density 2.30 g/cm3, surface area 2617.58 m2/g, accessible volume 0.03 cm3/g