NaMg2(CO3)4 crystallizes in the cubic Fd-3c space group. Na(1) is bonded in a rectangular see-saw-like geometry to four equivalent O(3) atoms. All Na(1)-O(3) bond lengths are 2.22 Å. Mg(1) is bonded in a distorted octahedral geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Both Mg(1)-O(1) bond lengths are 2.15 Å. Both Mg(1)-O(2) bond lengths are 2.05 Å. Both Mg(1)-O(3) bond lengths are 2.15 Å. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The C(1)-O(1) bond length is 1.29 Å. The C(1)-O(2) bond length is 1.28 Å. The C(1)-O(3) bond length is 1.26 Å. There are three inequivalent O sites. In the first O site, O(2) is bonded in a bent 120 degrees geometry to one Mg(1) and one C(1) atom. In the second O site, O(1) is bonded in an L-shaped geometry to one Mg(1) and one C(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Na(1), one Mg(1), and one C(1) atom. Linkers: 192 [O]C([O])=O. Metal clusters: 48 [Na] ,96 [Mg]. The MOF has largest included sphere 9.17 A, density 1.03 g/cm3, surface area 3693.65 m2/g, accessible volume 0.60 cm3/g