CaGa4(WO6)2 crystallizes in the tetragonal P-4 space group. Ca(1) is bonded in a 4-coordinate geometry to four equivalent O(1) atoms. W(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form WO6 octahedra that share corners with four equivalent Ga(1)O6 octahedra, corners with four equivalent Ga(2)O6 octahedra,  an edgeedge with one Ga(1)O6 octahedra, and  an edgeedge with one Ga(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-55°. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form distorted GaO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent Ga(1)O6 octahedra,  an edgeedge with one W(1)O6 octahedra, and  an edgeedge with one Ga(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-55°. In the second Ga site, Ga(2) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form GaO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent Ga(2)O6 octahedra,  an edgeedge with one W(1)O6 octahedra, and  an edgeedge with one Ga(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-52°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ca(1), one W(1), and two equivalent Ga(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one W(1) and two equivalent Ga(2) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one W(1), one Ga(1), and one Ga(2) atom.
CaGa4(WO6)2 crystallizes in the tetragonal P-4 space group. Ca(1) is bonded in a 4-coordinate geometry to four equivalent O(1) atoms. All Ca(1)-O(1) bond lengths are 2.09 Å. W(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form WO6 octahedra that share corners with four equivalent Ga(1)O6 octahedra, corners with four equivalent Ga(2)O6 octahedra,  an edgeedge with one Ga(1)O6 octahedra, and  an edgeedge with one Ga(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-55°. Both W(1)-O(1) bond lengths are 2.04 Å. Both W(1)-O(2) bond lengths are 1.98 Å. Both W(1)-O(3) bond lengths are 2.05 Å. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form distorted GaO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent Ga(1)O6 octahedra,  an edgeedge with one W(1)O6 octahedra, and  an edgeedge with one Ga(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-55°. Both Ga(1)-O(3) bond lengths are 1.92 Å. There are two shorter (2.14 Å) and two longer (2.20 Å) Ga(1)-O(1) bond lengths. In the second Ga site, Ga(2) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form GaO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent Ga(2)O6 octahedra,  an edgeedge with one W(1)O6 octahedra, and  an edgeedge with one Ga(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-52°. Both Ga(2)-O(3) bond lengths are 2.11 Å. There are two shorter (2.00 Å) and two longer (2.10 Å) Ga(2)-O(2) bond lengths. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ca(1), one W(1), and two equivalent Ga(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one W(1) and two equivalent Ga(2) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one W(1), one Ga(1), and one Ga(2) atom.