Na4CO4 crystallizes in the monoclinic C2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(2) atoms. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(2) atoms. C(1) is bonded in a tetrahedral geometry to two equivalent O(1) and two equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one C(1) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one C(1) atom.
Na4CO4 crystallizes in the monoclinic C2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(2) atoms. There is one shorter (2.34 Å) and one longer (2.38 Å) Na(1)-O(1) bond length. There is one shorter (2.21 Å) and one longer (2.23 Å) Na(1)-O(2) bond length. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(2) atoms. There is one shorter (2.33 Å) and one longer (2.36 Å) Na(2)-O(1) bond length. There is one shorter (2.32 Å) and one longer (2.49 Å) Na(2)-O(2) bond length. C(1) is bonded in a tetrahedral geometry to two equivalent O(1) and two equivalent O(2) atoms. Both C(1)-O(1) bond lengths are 1.42 Å. Both C(1)-O(2) bond lengths are 1.44 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one C(1) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one C(1) atom.