NiH(CO)5CO2 crystallizes in the triclinic P-1 space group. The structure consists of six carbon dioxide molecules inside a NiH(CO)5 framework. In the NiH(CO)5 framework, there are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(10), one O(2), one O(5), one O(6), and one O(9) atom to form edge-sharing NiO6 octahedra. The Ni(1)-O(1) bond length is 2.01 Å. The Ni(1)-O(10) bond length is 2.34 Å. The Ni(1)-O(2) bond length is 2.00 Å. The Ni(1)-O(5) bond length is 1.99 Å. The Ni(1)-O(6) bond length is 2.05 Å. The Ni(1)-O(9) bond length is 2.02 Å. In the second Ni site, Ni(2) is bonded to one O(11), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form edge-sharing NiO6 octahedra. The Ni(2)-O(11) bond length is 2.34 Å. The Ni(2)-O(2) bond length is 2.01 Å. The Ni(2)-O(3) bond length is 2.00 Å. The Ni(2)-O(4) bond length is 2.05 Å. The Ni(2)-O(6) bond length is 1.99 Å. The Ni(2)-O(7) bond length is 2.02 Å. In the third Ni site, Ni(3) is bonded to one O(1), one O(12), one O(3), one O(4), one O(5), and one O(8) atom to form edge-sharing NiO6 octahedra. The Ni(3)-O(1) bond length is 2.00 Å. The Ni(3)-O(12) bond length is 2.34 Å. The Ni(3)-O(3) bond length is 2.01 Å. The Ni(3)-O(4) bond length is 1.99 Å. The Ni(3)-O(5) bond length is 2.05 Å. The Ni(3)-O(8) bond length is 2.02 Å. There are thirteen inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(4,6); one O(1); and one O(7) atom. The C(1)-C(4,6) bond length is 1.48 Å. The C(1)-O(1) bond length is 1.29 Å. The C(1)-O(7) bond length is 1.27 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one C(5), one O(2), and one O(8) atom. The C(2)-C(5) bond length is 1.48 Å. The C(2)-O(2) bond length is 1.29 Å. The C(2)-O(8) bond length is 1.27 Å. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one C(4,6); one O(3); and one O(9) atom. The C(3)-C(4,6) bond length is 1.48 Å. The C(3)-O(3) bond length is 1.29 Å. The C(3)-O(9) bond length is 1.27 Å. In the fourth C site, C(4,6) is bonded in a trigonal planar geometry to one C(1); one C(10); and one C(7,9) atom. The C(4,6)-C(10) bond length is 1.43 Å. The C(4,6)-C(7,9) bond length is 1.40 Å. In the fifth C site, C(5) is bonded in a trigonal planar geometry to one C(11), one C(2), and one C(8) atom. The C(5)-C(11) bond length is 1.43 Å. The C(5)-C(8) bond length is 1.40 Å. In the sixth C site, C(7,9) is bonded in a distorted trigonal planar geometry to one C(10); one C(4,6); and one H(1,3) atom. The C(7,9)-C(10) bond length is 1.40 Å. The C(7,9)-H(1,3) bond length is 1.09 Å. In the seventh C site, C(8) is bonded in a distorted trigonal planar geometry to one C(11), one C(5), and one H(2) atom. The C(8)-C(11) bond length is 1.40 Å. The C(8)-H(2) bond length is 1.09 Å. In the eighth C site, C(10) is bonded in a distorted single-bond geometry to one C(4,6); one C(7,9); and one O(4) atom. The C(10)-O(4) bond length is 1.34 Å. In the ninth C site, C(11) is bonded in a distorted single-bond geometry to one C(5), one C(8), and one O(5) atom. The C(11)-O(5) bond length is 1.34 Å. In the tenth C site, C(12) is bonded in a distorted single-bond geometry to one C(4,6); one C(7,9); and one O(6) atom. The C(12)-C(4,6) bond length is 1.43 Å. The C(12)-C(7,9) bond length is 1.40 Å. The C(12)-O(6) bond length is 1.34 Å. In the eleventh C site, C(13) is bonded in a linear geometry to one O(10) and one O(13) atom. The C(13)-O(10) bond length is 1.18 Å. The C(13)-O(13) bond length is 1.17 Å. In the twelfth C site, C(14) is bonded in a linear geometry to one O(11) and one O(14) atom. The C(14)-O(11) bond length is 1.18 Å. The C(14)-O(14) bond length is 1.17 Å. In the thirteenth C site, C(15) is bonded in a linear geometry to one O(12) and one O(15) atom. The C(15)-O(12) bond length is 1.18 Å. The C(15)-O(15) bond length is 1.17 Å. There are two inequivalent H sites. In the first H site, H(1,3) is bonded in a single-bond geometry to one C(7,9) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(8) atom. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ni(1), one Ni(3), and one C(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Ni(1), one Ni(2), and one C(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ni(2), one Ni(3), and one C(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ni(2), one Ni(3), and one C(10) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ni(1), one Ni(3), and one C(11) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ni(1), one Ni(2), and one C(12) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Ni(2) and one C(1) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Ni(3) and one C(2) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one Ni(1) and one C(3) atom. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one Ni(1) and one C(13) atom. In the eleventh O site, O(11) is bonded in a distorted bent 150 degrees geometry to one Ni(2) and one C(14) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one Ni(3) and one C(15) atom. In the thirteenth O site, O(13) is bonded in a single-bond geometry to one C(13) atom. In the fourteenth O site, O(14) is bonded in a single-bond geometry to one C(14) atom. In the fifteenth O site, O(15) is bonded in a single-bond geometry to one C(15) atom. Linkers: 3 [O]C(=O)c1cc([O])c(C([O])=O)cc1[O]. Metal clusters: 6 [Ni]. The MOF has largest included sphere 5.35 A, density 1.87 g/cm3, surface area 3678.32 m2/g, accessible volume 0.15 cm3/g