BaGa2Ge2O8 crystallizes in the monoclinic C2/c space group. Ba(1) is bonded in a 9-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), one O(8), and two equivalent O(1) atoms. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one O(1), one O(4), one O(6), and one O(8) atom to form GaO4 tetrahedra that share  a cornercorner with one Ge(1)O4 tetrahedra and corners with three equivalent Ge(2)O4 tetrahedra. In the second Ga site, Ga(2) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form GaO4 tetrahedra that share  a cornercorner with one Ge(2)O4 tetrahedra and corners with three equivalent Ge(1)O4 tetrahedra. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form GeO4 tetrahedra that share  a cornercorner with one Ga(1)O4 tetrahedra and corners with three equivalent Ga(2)O4 tetrahedra. In the second Ge site, Ge(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form GeO4 tetrahedra that share  a cornercorner with one Ga(2)O4 tetrahedra and corners with three equivalent Ga(1)O4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a 3-coordinate geometry to one Ba(1), one Ga(2), and one Ge(1) atom. In the second O site, O(8) is bonded in a 3-coordinate geometry to one Ba(1), one Ga(1), and one Ge(2) atom. In the third O site, O(1) is bonded to two equivalent Ba(1), one Ga(1), and one Ge(1) atom to form distorted edge-sharing OBa2GaGe tetrahedra. In the fourth O site, O(2) is bonded in a trigonal planar geometry to one Ba(1), one Ga(2), and one Ge(2) atom. In the fifth O site, O(6) is bonded in a bent 120 degrees geometry to one Ba(1), one Ga(1), and one Ge(2) atom. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1), one Ga(2), and one Ge(1) atom. In the seventh O site, O(4) is bonded in a 3-coordinate geometry to one Ba(1), one Ga(1), and one Ge(2) atom. In the eighth O site, O(5) is bonded in a bent 120 degrees geometry to one Ba(1), one Ga(2), and one Ge(1) atom.
BaGa2Ge2O8 crystallizes in the monoclinic C2/c space group. Ba(1) is bonded in a 9-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), one O(8), and two equivalent O(1) atoms. The Ba(1)-O(2) bond length is 2.62 Å. The Ba(1)-O(3) bond length is 2.88 Å. The Ba(1)-O(4) bond length is 2.92 Å. The Ba(1)-O(5) bond length is 3.22 Å. The Ba(1)-O(6) bond length is 3.15 Å. The Ba(1)-O(7) bond length is 2.89 Å. The Ba(1)-O(8) bond length is 2.91 Å. There is one shorter (2.83 Å) and one longer (2.86 Å) Ba(1)-O(1) bond length. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one O(1), one O(4), one O(6), and one O(8) atom to form GaO4 tetrahedra that share  a cornercorner with one Ge(1)O4 tetrahedra and corners with three equivalent Ge(2)O4 tetrahedra. The Ga(1)-O(1) bond length is 1.85 Å. The Ga(1)-O(4) bond length is 1.83 Å. The Ga(1)-O(6) bond length is 1.81 Å. The Ga(1)-O(8) bond length is 1.84 Å. In the second Ga site, Ga(2) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form GaO4 tetrahedra that share  a cornercorner with one Ge(2)O4 tetrahedra and corners with three equivalent Ge(1)O4 tetrahedra. The Ga(2)-O(2) bond length is 1.84 Å. The Ga(2)-O(3) bond length is 1.82 Å. The Ga(2)-O(5) bond length is 1.84 Å. The Ga(2)-O(7) bond length is 1.82 Å. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form GeO4 tetrahedra that share  a cornercorner with one Ga(1)O4 tetrahedra and corners with three equivalent Ga(2)O4 tetrahedra. The Ge(1)-O(1) bond length is 1.76 Å. The Ge(1)-O(3) bond length is 1.74 Å. The Ge(1)-O(5) bond length is 1.73 Å. The Ge(1)-O(7) bond length is 1.75 Å. In the second Ge site, Ge(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form GeO4 tetrahedra that share  a cornercorner with one Ga(2)O4 tetrahedra and corners with three equivalent Ga(1)O4 tetrahedra. The Ge(2)-O(2) bond length is 1.75 Å. The Ge(2)-O(4) bond length is 1.74 Å. The Ge(2)-O(6) bond length is 1.75 Å. The Ge(2)-O(8) bond length is 1.74 Å. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a 3-coordinate geometry to one Ba(1), one Ga(2), and one Ge(1) atom. In the second O site, O(8) is bonded in a 3-coordinate geometry to one Ba(1), one Ga(1), and one Ge(2) atom. In the third O site, O(1) is bonded to two equivalent Ba(1), one Ga(1), and one Ge(1) atom to form distorted edge-sharing OBa2GaGe tetrahedra. In the fourth O site, O(2) is bonded in a trigonal planar geometry to one Ba(1), one Ga(2), and one Ge(2) atom. In the fifth O site, O(6) is bonded in a bent 120 degrees geometry to one Ba(1), one Ga(1), and one Ge(2) atom. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1), one Ga(2), and one Ge(1) atom. In the seventh O site, O(4) is bonded in a 3-coordinate geometry to one Ba(1), one Ga(1), and one Ge(2) atom. In the eighth O site, O(5) is bonded in a bent 120 degrees geometry to one Ba(1), one Ga(2), and one Ge(1) atom.