Na5GaGe2 crystallizes in the monoclinic P2_1/m space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 3-coordinate geometry to one Ge(2) and two equivalent Ge(1) atoms. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to two equivalent Ga(1), one Ge(1), and two equivalent Ge(2) atoms. In the third Na site, Na(3) is bonded in a distorted trigonal planar geometry to one Ge(2) and two equivalent Ge(1) atoms. Ga(1) is bonded in a 2-coordinate geometry to four equivalent Na(2), one Ge(1), and one Ge(2) atom. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 9-coordinate geometry to two equivalent Na(2), two equivalent Na(3), four equivalent Na(1), and one Ga(1) atom. In the second Ge site, Ge(2) is bonded in a 8-coordinate geometry to one Na(3), two equivalent Na(1), four equivalent Na(2), and one Ga(1) atom.
Na5GaGe2 crystallizes in the monoclinic P2_1/m space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 3-coordinate geometry to one Ge(2) and two equivalent Ge(1) atoms. The Na(1)-Ge(2) bond length is 3.23 Å. There is one shorter (3.13 Å) and one longer (3.20 Å) Na(1)-Ge(1) bond length. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to two equivalent Ga(1), one Ge(1), and two equivalent Ge(2) atoms. There is one shorter (3.25 Å) and one longer (3.31 Å) Na(2)-Ga(1) bond length. The Na(2)-Ge(1) bond length is 3.17 Å. There is one shorter (3.08 Å) and one longer (3.30 Å) Na(2)-Ge(2) bond length. In the third Na site, Na(3) is bonded in a distorted trigonal planar geometry to one Ge(2) and two equivalent Ge(1) atoms. The Na(3)-Ge(2) bond length is 2.97 Å. There is one shorter (2.99 Å) and one longer (3.04 Å) Na(3)-Ge(1) bond length. Ga(1) is bonded in a 2-coordinate geometry to four equivalent Na(2), one Ge(1), and one Ge(2) atom. The Ga(1)-Ge(1) bond length is 2.38 Å. The Ga(1)-Ge(2) bond length is 2.37 Å. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 9-coordinate geometry to two equivalent Na(2), two equivalent Na(3), four equivalent Na(1), and one Ga(1) atom. In the second Ge site, Ge(2) is bonded in a 8-coordinate geometry to one Na(3), two equivalent Na(1), four equivalent Na(2), and one Ga(1) atom.