NiH12(CO)8 crystallizes in the monoclinic C2/c space group. Ni(1) is bonded in an octahedral geometry to one O(4), one O(5), two equivalent O(1), and two equivalent O(3) atoms. The Ni(1)-O(4) bond length is 2.08 Å. The Ni(1)-O(5) bond length is 1.99 Å. Both Ni(1)-O(1) bond lengths are 2.08 Å. Both Ni(1)-O(3) bond lengths are 2.14 Å. There are four inequivalent C sites. In the first C site, C(4) is bonded in a distorted single-bond geometry to one C(2) and one H(2) atom. The C(4)-C(2) bond length is 1.40 Å. The C(4)-H(2) bond length is 1.09 Å. In the second C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(2), one O(1), and one O(2) atom. The C(1)-C(2) bond length is 1.49 Å. The C(1)-O(1) bond length is 1.28 Å. The C(1)-O(2) bond length is 1.27 Å. In the third C site, C(2) is bonded in a trigonal planar geometry to one C(1), one C(3), and one C(4) atom. The C(2)-C(3) bond length is 1.40 Å. In the fourth C site, C(3) is bonded in a distorted single-bond geometry to one C(2) and one H(1) atom. The C(3)-H(1) bond length is 1.09 Å. There are six 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(4) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(4) atom. The H(3)-O(4) bond length is 0.98 Å. In the fourth H site, H(4) is bonded in a distorted linear geometry to one O(2) and one O(5) atom. The H(4)-O(2) bond length is 1.62 Å. The H(4)-O(5) bond length is 1.00 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(1) and one O(3) atom. The H(5)-O(1) bond length is 1.68 Å. The H(5)-O(3) bond length is 1.00 Å. In the sixth H site, H(6) is bonded in a distorted linear geometry to one O(2) and one O(3) atom. The H(6)-O(2) bond length is 1.59 Å. The H(6)-O(3) bond length is 1.02 Å. There are five inequivalent O sites. In the first O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Ni(1) and two equivalent H(3) atoms. In the second O site, O(5) is bonded in a distorted trigonal planar geometry to one Ni(1) and two equivalent H(4) atoms. In the third O site, O(3) is bonded in a distorted water-like geometry to one Ni(1), one H(5), and one H(6) atom. In the fourth O site, O(1) is bonded in a distorted trigonal planar geometry to one Ni(1), one C(1), and one H(5) atom. In the fifth O site, O(2) is bonded in a trigonal planar geometry to one C(1), one H(4), and one H(6) atom. Linkers: 2 [O]C(=O)c1ccc(C([O])=O)cc1. Metal clusters: 2 O.O.O.O.O=[C]O[Ni]O[C]=O. The MOF has largest included sphere 1.88 A, density 1.76 g/cm3, surface area 4173.52 m2/g, accessible volume 0.10 cm3/g