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BaGa2 is hexagonal omega structure structured and crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Ba is bonded to twelve equivalent Ga atoms to form a mixture of edge and face-sharing BaGa12 cuboctahedra. All Ba–Ga bond lengths are 3.64 Å. Ga is bonded in a 9-coordinate geometry to six equivalent Ba and three equivalent Ga atoms. All Ga–Ga bond lengths are 2.59 Å.
BaGa2Ge2O8 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.65–3.26 Å. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share corners with four GeO4 tetrahedra. There are a spread of Ga–O bond distances ranging from 1.83–1.87 Å. In the second Ga3+ site, Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share corners with four GeO4 tetrahedra. There is two shorter (1.84 Å) and two longer (1.86 Å) Ga–O bond length. There are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with four GaO4 tetrahedra. There are a spread of Ge–O bond distances ranging from 1.75–1.79 Å. In the second Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with four GaO4 tetrahedra. There is two shorter (1.76 Å) and two longer (1.77 Å) Ge–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, one Ga3+, and one Ge4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, one Ga3+, and one Ge4+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, one Ga3+, and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ba2+, one Ga3+, and one Ge4+ atom. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to one Ba2+, one Ga3+, and one Ge4+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, one Ga3+, and one Ge4+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, one Ga3+, and one Ge4+ atom. In the eighth O2- site, O2- is bonded in a bent 120 degrees geometry to one Ba2+, one Ga3+, and one Ge4+ atom.
BaGa2Si2O8 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.67–3.29 Å. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share corners with four SiO4 tetrahedra. There are a spread of Ga–O bond distances ranging from 1.82–1.87 Å. In the second Ga3+ site, Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share corners with four SiO4 tetrahedra. There are a spread of Ga–O bond distances ranging from 1.83–1.86 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four GaO4 tetrahedra. There is two shorter (1.64 Å) and two longer (1.65 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four GaO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ba2+, one Ga3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+, one Ga3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, one Ga3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, one Ga3+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+, one Ga3+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ba2+, one Ga3+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to one Ba2+, one Ga3+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+, one Ga3+, and one Si4+ atom.