BiAlGa2(BO3)4 is Calcite-derived structured and crystallizes in the monoclinic C2 space group. Ga(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form GaO6 octahedra that share corners with two equivalent Bi(1)O6 pentagonal pyramids,  an edgeedge with one Ga(1)O6 octahedra, and  an edgeedge with one Al(1)O6 octahedra. Al(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form AlO6 octahedra that share corners with two equivalent Bi(1)O6 pentagonal pyramids and edges with two equivalent Ga(1)O6 octahedra. There are three inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(1), one O(5), and one O(7) atom. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(2) and two equivalent O(6) atoms. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(4) and two equivalent O(3) atoms. Bi(1) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms to form distorted BiO6 pentagonal pyramids that share corners with two equivalent Al(1)O6 octahedra and corners with four equivalent Ga(1)O6 octahedra. The corner-sharing octahedral tilt angles are 60°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ga(1), one Al(1), and one B(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Ga(1) and one B(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Ga(1), one Al(1), and one B(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Ga(1) and one B(3) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Al(1), one B(1), and one Bi(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ga(1), one B(2), and one Bi(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Ga(1), one B(1), and one Bi(1) atom.
BiAlGa2(BO3)4 is Calcite-derived structured and crystallizes in the monoclinic C2 space group. Ga(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form GaO6 octahedra that share corners with two equivalent Bi(1)O6 pentagonal pyramids,  an edgeedge with one Ga(1)O6 octahedra, and  an edgeedge with one Al(1)O6 octahedra. The Ga(1)-O(1) bond length is 2.04 Å. The Ga(1)-O(2) bond length is 2.02 Å. The Ga(1)-O(3) bond length is 2.02 Å. The Ga(1)-O(4) bond length is 2.01 Å. The Ga(1)-O(6) bond length is 1.94 Å. The Ga(1)-O(7) bond length is 1.95 Å. Al(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form AlO6 octahedra that share corners with two equivalent Bi(1)O6 pentagonal pyramids and edges with two equivalent Ga(1)O6 octahedra. Both Al(1)-O(1) bond lengths are 1.97 Å. Both Al(1)-O(3) bond lengths are 1.96 Å. Both Al(1)-O(5) bond lengths are 1.90 Å. There are three inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(1), one O(5), and one O(7) atom. The B(1)-O(1) bond length is 1.39 Å. The B(1)-O(5) bond length is 1.38 Å. The B(1)-O(7) bond length is 1.38 Å. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(2) and two equivalent O(6) atoms. The B(2)-O(2) bond length is 1.39 Å. Both B(2)-O(6) bond lengths are 1.37 Å. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(4) and two equivalent O(3) atoms. The B(3)-O(4) bond length is 1.39 Å. Both B(3)-O(3) bond lengths are 1.40 Å. Bi(1) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms to form distorted BiO6 pentagonal pyramids that share corners with two equivalent Al(1)O6 octahedra and corners with four equivalent Ga(1)O6 octahedra. The corner-sharing octahedral tilt angles are 60°. Both Bi(1)-O(5) bond lengths are 2.44 Å. Both Bi(1)-O(6) bond lengths are 2.40 Å. Both Bi(1)-O(7) bond lengths are 2.39 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ga(1), one Al(1), and one B(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Ga(1) and one B(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Ga(1), one Al(1), and one B(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Ga(1) and one B(3) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Al(1), one B(1), and one Bi(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ga(1), one B(2), and one Bi(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Ga(1), one B(1), and one Bi(1) atom.