Pr3GaO6 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted PrO7 pentagonal bipyramids that share  a cornercorner with one Pr(2)O7 hexagonal pyramid, corners with four equivalent Pr(1)O7 pentagonal bipyramids, corners with three equivalent Ga(1)O4 tetrahedra, edges with three equivalent Pr(2)O7 hexagonal pyramids, edges with two equivalent Pr(1)O7 pentagonal bipyramids,  an edgeedge with one Ga(1)O4 tetrahedra, and  a faceface with one Pr(1)O7 pentagonal bipyramid. In the second Pr site, Pr(2) is bonded to one O(4), two equivalent O(2), and four equivalent O(1) atoms to form distorted PrO7 hexagonal pyramids that share corners with two equivalent Pr(1)O7 pentagonal bipyramids,  a cornercorner with one Ga(1)O4 tetrahedra, edges with two equivalent Pr(2)O7 hexagonal pyramids, edges with six equivalent Pr(1)O7 pentagonal bipyramids, and  an edgeedge with one Ga(1)O4 tetrahedra. Ga(1) is bonded to one O(3), one O(4), and two equivalent O(2) atoms to form GaO4 tetrahedra that share  a cornercorner with one Pr(2)O7 hexagonal pyramid, corners with six equivalent Pr(1)O7 pentagonal bipyramids,  an edgeedge with one Pr(2)O7 hexagonal pyramid, and edges with two equivalent Pr(1)O7 pentagonal bipyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Pr(1) and two equivalent Pr(2) atoms to form OPr4 tetrahedra that share corners with two equivalent O(1)Pr4 tetrahedra, corners with six equivalent O(2)Pr3Ga trigonal pyramids, edges with three equivalent O(1)Pr4 tetrahedra, and  an edgeedge with one O(2)Pr3Ga trigonal pyramid. In the second O site, O(2) is bonded to one Pr(2), two equivalent Pr(1), and one Ga(1) atom to form distorted OPr3Ga trigonal pyramids that share corners with six equivalent O(1)Pr4 tetrahedra, corners with two equivalent O(2)Pr3Ga trigonal pyramids,  an edgeedge with one O(1)Pr4 tetrahedra, and  an edgeedge with one O(2)Pr3Ga trigonal pyramid. In the third O site, O(3) is bonded in a 5-coordinate geometry to four equivalent Pr(1) and one Ga(1) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Pr(2), two equivalent Pr(1), and one Ga(1) atom.
Pr3GaO6 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted PrO7 pentagonal bipyramids that share  a cornercorner with one Pr(2)O7 hexagonal pyramid, corners with four equivalent Pr(1)O7 pentagonal bipyramids, corners with three equivalent Ga(1)O4 tetrahedra, edges with three equivalent Pr(2)O7 hexagonal pyramids, edges with two equivalent Pr(1)O7 pentagonal bipyramids,  an edgeedge with one Ga(1)O4 tetrahedra, and  a faceface with one Pr(1)O7 pentagonal bipyramid. The Pr(1)-O(4) bond length is 2.50 Å. There is one shorter (2.32 Å) and one longer (2.35 Å) Pr(1)-O(1) bond length. There is one shorter (2.40 Å) and one longer (2.49 Å) Pr(1)-O(2) bond length. There is one shorter (2.66 Å) and one longer (2.72 Å) Pr(1)-O(3) bond length. In the second Pr site, Pr(2) is bonded to one O(4), two equivalent O(2), and four equivalent O(1) atoms to form distorted PrO7 hexagonal pyramids that share corners with two equivalent Pr(1)O7 pentagonal bipyramids,  a cornercorner with one Ga(1)O4 tetrahedra, edges with two equivalent Pr(2)O7 hexagonal pyramids, edges with six equivalent Pr(1)O7 pentagonal bipyramids, and  an edgeedge with one Ga(1)O4 tetrahedra. The Pr(2)-O(4) bond length is 2.55 Å. Both Pr(2)-O(2) bond lengths are 2.58 Å. All Pr(2)-O(1) bond lengths are 2.39 Å. Ga(1) is bonded to one O(3), one O(4), and two equivalent O(2) atoms to form GaO4 tetrahedra that share  a cornercorner with one Pr(2)O7 hexagonal pyramid, corners with six equivalent Pr(1)O7 pentagonal bipyramids,  an edgeedge with one Pr(2)O7 hexagonal pyramid, and edges with two equivalent Pr(1)O7 pentagonal bipyramids. The Ga(1)-O(3) bond length is 1.88 Å. The Ga(1)-O(4) bond length is 1.85 Å. Both Ga(1)-O(2) bond lengths are 1.88 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Pr(1) and two equivalent Pr(2) atoms to form OPr4 tetrahedra that share corners with two equivalent O(1)Pr4 tetrahedra, corners with six equivalent O(2)Pr3Ga trigonal pyramids, edges with three equivalent O(1)Pr4 tetrahedra, and  an edgeedge with one O(2)Pr3Ga trigonal pyramid. In the second O site, O(2) is bonded to one Pr(2), two equivalent Pr(1), and one Ga(1) atom to form distorted OPr3Ga trigonal pyramids that share corners with six equivalent O(1)Pr4 tetrahedra, corners with two equivalent O(2)Pr3Ga trigonal pyramids,  an edgeedge with one O(1)Pr4 tetrahedra, and  an edgeedge with one O(2)Pr3Ga trigonal pyramid. In the third O site, O(3) is bonded in a 5-coordinate geometry to four equivalent Pr(1) and one Ga(1) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Pr(2), two equivalent Pr(1), and one Ga(1) atom.