NaH7(CO)6 crystallizes in the orthorhombic P2_12_12_1 space group. Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(5), and two equivalent O(6) atoms. The Na(1)-O(1) bond length is 2.43 Å. The Na(1)-O(2) bond length is 2.51 Å. The Na(1)-O(3) bond length is 2.50 Å. The Na(1)-O(5) bond length is 2.44 Å. There is one shorter (2.44 Å) and one longer (2.64 Å) Na(1)-O(6) bond length. There are six inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(4) atom. The C(1)-O(1) bond length is 1.25 Å. The C(1)-O(4) bond length is 1.37 Å. In the second C site, C(2) is bonded in a distorted single-bond geometry to one O(2) atom. The C(2)-O(2) bond length is 1.38 Å. In the third C site, C(3) is bonded in a distorted single-bond geometry to one O(3) atom. The C(3)-O(3) bond length is 1.29 Å. In the fourth C site, C(4) is bonded in a distorted water-like geometry to one H(4) and one O(4) atom. The C(4)-H(4) bond length is 1.10 Å. The C(4)-O(4) bond length is 1.46 Å. In the fifth C site, C(5) is bonded in a distorted water-like geometry to one H(5) and one O(5) atom. The C(5)-H(5) bond length is 1.10 Å. The C(5)-O(5) bond length is 1.43 Å. In the sixth C site, C(6) is bonded in a distorted trigonal non-coplanar geometry to one H(6), one H(7), and one O(6) atom. The C(6)-H(6) bond length is 1.10 Å. The C(6)-H(7) bond length is 1.10 Å. The C(6)-O(6) bond length is 1.44 Å. There are seven inequivalent H sites. In the first H site, H(1) is bonded in a linear geometry to one O(2) and one O(3) atom. The H(1)-O(2) bond length is 1.05 Å. The H(1)-O(3) bond length is 1.47 Å. In the second H site, H(2) is bonded in a distorted single-bond geometry to one O(2) and one O(5) atom. The H(2)-O(2) bond length is 1.66 Å. The H(2)-O(5) bond length is 1.00 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(1) and one O(6) atom. The H(3)-O(1) bond length is 1.74 Å. The H(3)-O(6) bond length is 1.00 Å. 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(5) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one C(6) atom. In the seventh H site, H(7) is bonded in a single-bond geometry to one C(6) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one C(1), and one H(3) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one C(2), one H(1), and one H(2) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Na(1), one C(3), and one H(1) atom. In the fourth O site, O(4) is bonded in a water-like geometry to one C(1) and one C(4) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Na(1), one C(5), and one H(2) atom. In the sixth O site, O(6) is bonded in a distorted water-like geometry to two equivalent Na(1), one C(6), and one H(3) atom. Linkers: 4 [O]C1=C(O)C(=O)O[C@@H]1[C@@H](O)CO. Metal clusters: 4 [Na]. RCSR code: hcb. The MOF has largest included sphere 1.47 A, density 1.84 g/cm3, surface area 2818.65 m2/g, accessible volume 0.04 cm3/g