Na3GaB4O9 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(3), one O(4), one O(5), one O(6), and two equivalent O(1) atoms. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(2), one O(5), two equivalent O(4), and two equivalent O(6) atoms. Ga(1) is bonded to one O(3), one O(5), and two equivalent O(6) atoms to form GaO4 tetrahedra that share  a cornercorner with one B(1)O4 tetrahedra and  a cornercorner with one B(2)O4 tetrahedra. There are three inequivalent B sites. In the first B site, B(1) is bonded to one O(2), one O(5), and two equivalent O(1) atoms to form BO4 tetrahedra that share  a cornercorner with one Ga(1)O4 tetrahedra and  a cornercorner with one B(2)O4 tetrahedra. In the second B site, B(2) is bonded to one O(2), one O(3), and two equivalent O(4) atoms to form BO4 tetrahedra that share  a cornercorner with one Ga(1)O4 tetrahedra and  a cornercorner with one B(1)O4 tetrahedra. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(1), one O(4), and one O(6) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Na(1), one B(1), and one B(3) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(2), one B(1), and one B(2) atom. In the third O site, O(3) is bonded in a distorted tetrahedral geometry to two equivalent Na(1), one Ga(1), and one B(2) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one B(2), and one B(3) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(1), one Ga(1), and one B(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ga(1), and one B(3) atom.
Na3GaB4O9 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(3), one O(4), one O(5), one O(6), and two equivalent O(1) atoms. The Na(1)-O(3) bond length is 2.32 Å. The Na(1)-O(4) bond length is 2.59 Å. The Na(1)-O(5) bond length is 2.52 Å. The Na(1)-O(6) bond length is 2.42 Å. There is one shorter (2.40 Å) and one longer (2.63 Å) Na(1)-O(1) bond length. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(2), one O(5), two equivalent O(4), and two equivalent O(6) atoms. The Na(2)-O(2) bond length is 2.21 Å. The Na(2)-O(5) bond length is 2.60 Å. Both Na(2)-O(4) bond lengths are 2.35 Å. Both Na(2)-O(6) bond lengths are 2.51 Å. Ga(1) is bonded to one O(3), one O(5), and two equivalent O(6) atoms to form GaO4 tetrahedra that share  a cornercorner with one B(1)O4 tetrahedra and  a cornercorner with one B(2)O4 tetrahedra. The Ga(1)-O(3) bond length is 1.85 Å. The Ga(1)-O(5) bond length is 1.85 Å. Both Ga(1)-O(6) bond lengths are 1.89 Å. There are three inequivalent B sites. In the first B site, B(1) is bonded to one O(2), one O(5), and two equivalent O(1) atoms to form BO4 tetrahedra that share  a cornercorner with one Ga(1)O4 tetrahedra and  a cornercorner with one B(2)O4 tetrahedra. The B(1)-O(2) bond length is 1.45 Å. The B(1)-O(5) bond length is 1.47 Å. Both B(1)-O(1) bond lengths are 1.52 Å. In the second B site, B(2) is bonded to one O(2), one O(3), and two equivalent O(4) atoms to form BO4 tetrahedra that share  a cornercorner with one Ga(1)O4 tetrahedra and  a cornercorner with one B(1)O4 tetrahedra. The B(2)-O(2) bond length is 1.44 Å. The B(2)-O(3) bond length is 1.45 Å. Both B(2)-O(4) bond lengths are 1.54 Å. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(1), one O(4), and one O(6) atom. The B(3)-O(1) bond length is 1.39 Å. The B(3)-O(4) bond length is 1.38 Å. The B(3)-O(6) bond length is 1.39 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Na(1), one B(1), and one B(3) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(2), one B(1), and one B(2) atom. In the third O site, O(3) is bonded in a distorted tetrahedral geometry to two equivalent Na(1), one Ga(1), and one B(2) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one B(2), and one B(3) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(1), one Ga(1), and one B(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ga(1), and one B(3) atom.