Ba6Pr2Ga4O15 crystallizes in the monoclinic P2/c space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 10-coordinate geometry to one O(5), one O(6), one O(7), two equivalent O(2), two equivalent O(4), and three equivalent O(8) atoms. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(1), one O(5), one O(6), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms. In the fourth Ba site, Ba(4) is bonded in a 8-coordinate geometry to two equivalent O(5), two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms. Pr(1) is bonded to one O(2), one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form PrO6 octahedra that share corners with two equivalent Ga(2)O4 tetrahedra and corners with four equivalent Ga(1)O4 tetrahedra. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one O(2), one O(3), one O(4), and one O(8) atom to form GaO4 tetrahedra that share corners with four equivalent Pr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-41°. In the second Ga site, Ga(2) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form GaO4 tetrahedra that share corners with two equivalent Pr(1)O6 octahedra and  a cornercorner with one Ga(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 13-39°. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), one Pr(1), and one Ga(1) atom. In the second O site, O(5) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one Ba(4), and one Ga(2) atom. In the third O site, O(6) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(3), one Ba(4), one Pr(1), and one Ga(2) atom. In the fourth O site, O(7) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(3), one Ba(4), one Pr(1), and one Ga(2) atom. In the fifth O site, O(8) is bonded in a 2-coordinate geometry to one Ba(4), three equivalent Ba(1), one Pr(1), and one Ga(1) atom. In the sixth O site, O(1) is bonded in a distorted linear geometry to two equivalent Ba(2), two equivalent Ba(3), and two equivalent Ga(2) atoms. In the seventh O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), one Pr(1), and one Ga(1) atom. In the eighth O site, O(3) is bonded in a 5-coordinate geometry to one Ba(3), two equivalent Ba(2), one Pr(1), and one Ga(1) atom.
Ba6Pr2Ga4O15 crystallizes in the monoclinic P2/c space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 10-coordinate geometry to one O(5), one O(6), one O(7), two equivalent O(2), two equivalent O(4), and three equivalent O(8) atoms. The Ba(1)-O(5) bond length is 2.53 Å. The Ba(1)-O(6) bond length is 2.80 Å. The Ba(1)-O(7) bond length is 3.39 Å. There is one shorter (3.04 Å) and one longer (3.12 Å) Ba(1)-O(2) bond length. There is one shorter (3.01 Å) and one longer (3.04 Å) Ba(1)-O(4) bond length. There are a spread of Ba(1)-O(8) bond distances ranging from 3.00-3.34 Å. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(1), one O(5), one O(6), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. The Ba(2)-O(1) bond length is 3.01 Å. The Ba(2)-O(5) bond length is 2.77 Å. The Ba(2)-O(6) bond length is 2.97 Å. There is one shorter (2.80 Å) and one longer (3.17 Å) Ba(2)-O(2) bond length. There is one shorter (3.07 Å) and one longer (3.10 Å) Ba(2)-O(3) bond length. There is one shorter (2.91 Å) and one longer (3.22 Å) Ba(2)-O(4) bond length. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms. There is one shorter (2.96 Å) and one longer (3.16 Å) Ba(3)-O(1) bond length. Both Ba(3)-O(3) bond lengths are 2.66 Å. Both Ba(3)-O(6) bond lengths are 3.17 Å. Both Ba(3)-O(7) bond lengths are 2.79 Å. In the fourth Ba site, Ba(4) is bonded in a 8-coordinate geometry to two equivalent O(5), two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms. Both Ba(4)-O(5) bond lengths are 2.92 Å. Both Ba(4)-O(6) bond lengths are 2.94 Å. Both Ba(4)-O(7) bond lengths are 2.74 Å. Both Ba(4)-O(8) bond lengths are 2.99 Å. Pr(1) is bonded to one O(2), one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form PrO6 octahedra that share corners with two equivalent Ga(2)O4 tetrahedra and corners with four equivalent Ga(1)O4 tetrahedra. The Pr(1)-O(2) bond length is 2.34 Å. The Pr(1)-O(3) bond length is 2.46 Å. The Pr(1)-O(4) bond length is 2.32 Å. The Pr(1)-O(6) bond length is 2.38 Å. The Pr(1)-O(7) bond length is 2.40 Å. The Pr(1)-O(8) bond length is 2.39 Å. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one O(2), one O(3), one O(4), and one O(8) atom to form GaO4 tetrahedra that share corners with four equivalent Pr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-41°. The Ga(1)-O(2) bond length is 1.88 Å. The Ga(1)-O(3) bond length is 1.88 Å. The Ga(1)-O(4) bond length is 1.89 Å. The Ga(1)-O(8) bond length is 1.87 Å. In the second Ga site, Ga(2) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form GaO4 tetrahedra that share corners with two equivalent Pr(1)O6 octahedra and  a cornercorner with one Ga(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 13-39°. The Ga(2)-O(1) bond length is 1.88 Å. The Ga(2)-O(5) bond length is 1.83 Å. The Ga(2)-O(6) bond length is 1.89 Å. The Ga(2)-O(7) bond length is 1.85 Å. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), one Pr(1), and one Ga(1) atom. In the second O site, O(5) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one Ba(4), and one Ga(2) atom. In the third O site, O(6) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(3), one Ba(4), one Pr(1), and one Ga(2) atom. In the fourth O site, O(7) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(3), one Ba(4), one Pr(1), and one Ga(2) atom. In the fifth O site, O(8) is bonded in a 2-coordinate geometry to one Ba(4), three equivalent Ba(1), one Pr(1), and one Ga(1) atom. In the sixth O site, O(1) is bonded in a distorted linear geometry to two equivalent Ba(2), two equivalent Ba(3), and two equivalent Ga(2) atoms. In the seventh O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), one Pr(1), and one Ga(1) atom. In the eighth O site, O(3) is bonded in a 5-coordinate geometry to one Ba(3), two equivalent Ba(2), one Pr(1), and one Ga(1) atom.