Na(CO2)3(CH3)3 crystallizes in the cubic P2_13 space group. The structure consists of twelve 02329_fluka molecules inside a Na(CO2)3 framework. In the Na(CO2)3 framework, Na(1) is bonded in a distorted octahedral geometry to three equivalent O(1) and three equivalent O(2) atoms. All Na(1)-O(1) bond lengths are 2.37 Å. All Na(1)-O(2) bond lengths are 2.40 Å. C(1) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(2) atom. The C(1)-O(1) bond length is 1.26 Å. The C(1)-O(2) bond length is 1.27 Å. There are two inequivalent O sites. In the first O site, O(2) is bonded in a bent 150 degrees geometry to one Na(1) and one C(1) atom. In the second O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Na(1) and one C(1) atom. Linkers: 12 CC([O])=O. Metal clusters: 4 [Na]. The MOF has largest included sphere 4.24 A, density 0.98 g/cm3, surface area 5778.44 m2/g, accessible volume 0.55 cm3/g