Na3Hg2 crystallizes in the tetragonal P4_2/mnm space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted square co-planar geometry to four equivalent Hg(1) atoms. In the second Na site, Na(3) is bonded in a 6-coordinate geometry to six equivalent Hg(1) atoms. In the third Na site, Na(2) is bonded in a 6-coordinate geometry to six equivalent Hg(1) atoms. Hg(1) is bonded in a 10-coordinate geometry to two equivalent Na(1), three equivalent Na(2), three equivalent Na(3), and two equivalent Hg(1) atoms.
Na3Hg2 crystallizes in the tetragonal P4_2/mnm space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted square co-planar geometry to four equivalent Hg(1) atoms. All Na(1)-Hg(1) bond lengths are 3.33 Å. In the second Na site, Na(3) is bonded in a 6-coordinate geometry to six equivalent Hg(1) atoms. There are two shorter (3.12 Å) and four longer (3.22 Å) Na(3)-Hg(1) bond lengths. In the third Na site, Na(2) is bonded in a 6-coordinate geometry to six equivalent Hg(1) atoms. There are two shorter (3.15 Å) and four longer (3.28 Å) Na(2)-Hg(1) bond lengths. Hg(1) is bonded in a 10-coordinate geometry to two equivalent Na(1), three equivalent Na(2), three equivalent Na(3), and two equivalent Hg(1) atoms. There is one shorter (2.98 Å) and one longer (3.00 Å) Hg(1)-Hg(1) bond length.