NaCo3H9(C9O7)2 crystallizes in the monoclinic C2 space group. Na(1) is bonded in a 3-coordinate geometry to one O(12) and two equivalent O(14) atoms. The Na(1)-O(12) bond length is 2.30 Å. There is one shorter (2.35 Å) and one longer (2.59 Å) Na(1)-O(14) bond length. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded in a 4-coordinate geometry to one O(1), one O(13), one O(6), and one O(9) atom. The Co(1)-O(1) bond length is 1.99 Å. The Co(1)-O(13) bond length is 1.98 Å. The Co(1)-O(6) bond length is 2.58 Å. The Co(1)-O(9) bond length is 2.04 Å. In the second Co site, Co(2) is bonded to one O(13), one O(2), one O(3), one O(6), and one O(7) atom to form corner-sharing CoO5 square pyramids. The corner-sharing octahedral tilt angles are 68°. The Co(2)-O(13) bond length is 2.05 Å. The Co(2)-O(2) bond length is 2.08 Å. The Co(2)-O(3) bond length is 2.11 Å. The Co(2)-O(6) bond length is 2.22 Å. The Co(2)-O(7) bond length is 2.07 Å. In the third Co site, Co(3) is bonded to one O(10), one O(11), one O(12), one O(13), one O(5), and one O(8) atom to form distorted corner-sharing CoO6 octahedra. The Co(3)-O(10) bond length is 2.12 Å. The Co(3)-O(11) bond length is 2.21 Å. The Co(3)-O(12) bond length is 2.19 Å. The Co(3)-O(13) bond length is 2.04 Å. The Co(3)-O(5) bond length is 2.11 Å. The Co(3)-O(8) bond length is 2.04 Å. There are eighteen inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one C(2), one C(6), and one C(7) atom. The C(1)-C(2) bond length is 1.40 Å. The C(1)-C(6) bond length is 1.40 Å. The C(1)-C(7) bond length is 1.51 Å. In the second C site, C(2) is bonded in a single-bond geometry to one C(1), one C(3), and one H(3) atom. The C(2)-C(3) bond length is 1.38 Å. The C(2)-H(3) bond length is 0.95 Å. In the third C site, C(3) is bonded in a trigonal planar geometry to one C(2), one C(4), and one C(8) atom. The C(3)-C(4) bond length is 1.38 Å. The C(3)-C(8) bond length is 1.51 Å. In the fourth C site, C(4) is bonded in a single-bond geometry to one C(3), one C(5), and one H(4) atom. The C(4)-C(5) bond length is 1.41 Å. The C(4)-H(4) bond length is 0.95 Å. In the fifth C site, C(5) is bonded in a trigonal planar geometry to one C(4), one C(6), and one C(9) atom. The C(5)-C(6) bond length is 1.40 Å. The C(5)-C(9) bond length is 1.51 Å. In the sixth C site, C(6) is bonded in a distorted single-bond geometry to one C(1), one C(5), and one H(5) atom. The C(6)-H(5) bond length is 0.95 Å. In the seventh C site, C(7) is bonded in a distorted bent 120 degrees geometry to one C(1), one O(1), and one O(2) atom. The C(7)-O(1) bond length is 1.24 Å. The C(7)-O(2) bond length is 1.24 Å. In the eighth C site, C(8) is bonded in a distorted bent 120 degrees geometry to one C(3), one O(3), and one O(4) atom. The C(8)-O(3) bond length is 1.27 Å. The C(8)-O(4) bond length is 1.25 Å. In the ninth C site, C(9) is bonded in a bent 120 degrees geometry to one C(5), one O(5), and one O(6) atom. The C(9)-O(5) bond length is 1.26 Å. The C(9)-O(6) bond length is 1.26 Å. In the tenth C site, C(10) is bonded in a trigonal planar geometry to one C(11), one C(15), and one C(16) atom. The C(10)-C(11) bond length is 1.38 Å. The C(10)-C(15) bond length is 1.40 Å. The C(10)-C(16) bond length is 1.51 Å. In the eleventh C site, C(11) is bonded in a distorted single-bond geometry to one C(10), one C(12), and one H(6) atom. The C(11)-C(12) bond length is 1.40 Å. The C(11)-H(6) bond length is 0.95 Å. In the twelfth C site, C(12) is bonded in a trigonal planar geometry to one C(11), one C(13), and one C(17) atom. The C(12)-C(13) bond length is 1.39 Å. The C(12)-C(17) bond length is 1.52 Å. In the thirteenth C site, C(13) is bonded in a single-bond geometry to one C(12), one C(14), and one H(7) atom. The C(13)-C(14) bond length is 1.41 Å. The C(13)-H(7) bond length is 0.95 Å. In the fourteenth C site, C(14) is bonded in a trigonal planar geometry to one C(13), one C(15), and one C(18) atom. The C(14)-C(15) bond length is 1.40 Å. The C(14)-C(18) bond length is 1.50 Å. In the fifteenth C site, C(15) is bonded in a distorted single-bond geometry to one C(10), one C(14), and one H(8) atom. The C(15)-H(8) bond length is 0.95 Å. In the sixteenth C site, C(16) is bonded in a distorted bent 120 degrees geometry to one C(10), one O(7), and one O(8) atom. The C(16)-O(7) bond length is 1.24 Å. The C(16)-O(8) bond length is 1.26 Å. In the seventeenth C site, C(17) is bonded in a distorted bent 120 degrees geometry to one C(12), one O(10), and one O(9) atom. The C(17)-O(10) bond length is 1.24 Å. The C(17)-O(9) bond length is 1.27 Å. In the eighteenth C site, C(18) is bonded in a bent 120 degrees geometry to one C(14), one O(11), and one O(12) atom. The C(18)-O(11) bond length is 1.24 Å. The C(18)-O(12) bond length is 1.29 Å. There are nine inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(14) atom. The H(1)-O(14) bond length is 0.85 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(14) atom. The H(2)-O(14) bond length is 0.83 Å. 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. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(6) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one C(11) atom. In the seventh H site, H(7) is bonded in a single-bond geometry to one C(13) atom. In the eighth H site, H(8) is bonded in a single-bond geometry to one C(15) atom. In the ninth H site, H(9) is bonded in a single-bond geometry to one O(13) atom. The H(9)-O(13) bond length is 0.83 Å. There are fourteen inequivalent O sites. In the first O site, O(5) is bonded in a bent 120 degrees geometry to one Co(3) and one C(9) atom. In the second O site, O(6) is bonded in a 3-coordinate geometry to one Co(1), one Co(2), and one C(9) atom. In the third O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Co(2) and one C(16) atom. In the fourth O site, O(8) is bonded in a bent 120 degrees geometry to one Co(3) and one C(16) atom. In the fifth O site, O(9) is bonded in a water-like geometry to one Co(1) and one C(17) atom. In the sixth O site, O(10) is bonded in a bent 150 degrees geometry to one Co(3) and one C(17) atom. In the seventh O site, O(11) is bonded in an L-shaped geometry to one Co(3) and one C(18) atom. In the eighth O site, O(12) is bonded in a 3-coordinate geometry to one Na(1), one Co(3), and one C(18) atom. In the ninth O site, O(13) is bonded in a distorted single-bond geometry to one Co(1), one Co(2), one Co(3), and one H(9) atom. In the tenth O site, O(14) is bonded in a distorted water-like geometry to two equivalent Na(1), one H(1), and one H(2) atom. In the eleventh O site, O(1) is bonded in a bent 120 degrees geometry to one Co(1) and one C(7) atom. In the twelfth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Co(2) and one C(7) atom. In the thirteenth O site, O(3) is bonded in a bent 120 degrees geometry to one Co(2) and one C(8) atom. In the fourteenth O site, O(4) is bonded in a single-bond geometry to one C(8) atom. Linkers: 8 [O]C(=O)c1cc(C([O])=O)cc(C([O])=O)c1. Metal clusters: 2 O.O.O=[C]O[Co]12O[C]O[Co](O)O[C]O[Co]3(O[C]O1)(O[C]O2)O[C]O3.O=[C]O[Co]12O[C]O[Co](O)O[C]O[Co]3(O[C]O1)(O[C]O2)O[C]O3.[Na].[Na]. The MOF has largest included sphere 6.67 A, density 1.16 g/cm3, surface area 3418.82 m2/g, accessible volume 0.37 cm3/g