BaSrGd4O8 crystallizes in the orthorhombic Pmc2_1 space group. Ba(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(4), two equivalent O(6), and two equivalent O(7) atoms. Sr(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), two equivalent O(5), and two equivalent O(8) atoms. There are four inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one O(5), one O(7), two equivalent O(2), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing GdO6 octahedra. The corner-sharing octahedral tilt angles range from 50-62°. In the second Gd site, Gd(2) is bonded to one O(6), one O(8), two equivalent O(1), and two equivalent O(5) atoms to form a mixture of corner and edge-sharing GdO6 octahedra. The corner-sharing octahedral tilt angles range from 51-62°. In the third Gd site, Gd(3) is bonded to one O(1), one O(3), two equivalent O(4), and two equivalent O(8) atoms to form a mixture of corner and edge-sharing GdO6 octahedra. The corner-sharing octahedral tilt angles range from 51-62°. In the fourth Gd site, Gd(4) is bonded to one O(2), one O(4), two equivalent O(3), and two equivalent O(7) atoms to form a mixture of corner and edge-sharing GdO6 octahedra. The corner-sharing octahedral tilt angles range from 50-62°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Sr(1), one Gd(3), and two equivalent Gd(2) atoms. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Ba(1), one Gd(4), and two equivalent Gd(1) atoms. In the third O site, O(3) is bonded to two equivalent Sr(1), one Gd(3), and two equivalent Gd(4) atoms to form OSr2Gd3 square pyramids that share corners with two equivalent O(5)Sr2Gd3 trigonal bipyramids, edges with two equivalent O(4)Ba2Gd3 square pyramids, edges with two equivalent O(3)Sr2Gd3 square pyramids, and  an edgeedge with one O(5)Sr2Gd3 trigonal bipyramid. In the fourth O site, O(4) is bonded to two equivalent Ba(1), one Gd(4), and two equivalent Gd(3) atoms to form OBa2Gd3 square pyramids that share corners with two equivalent O(6)Ba2Gd3 trigonal bipyramids, edges with two equivalent O(4)Ba2Gd3 square pyramids, edges with two equivalent O(3)Sr2Gd3 square pyramids, and  an edgeedge with one O(6)Ba2Gd3 trigonal bipyramid. In the fifth O site, O(5) is bonded to two equivalent Sr(1), one Gd(1), and two equivalent Gd(2) atoms to form distorted OSr2Gd3 trigonal bipyramids that share corners with two equivalent O(3)Sr2Gd3 square pyramids,  an edgeedge with one O(3)Sr2Gd3 square pyramid, edges with two equivalent O(6)Ba2Gd3 trigonal bipyramids, and edges with two equivalent O(5)Sr2Gd3 trigonal bipyramids. In the sixth O site, O(6) is bonded to two equivalent Ba(1), one Gd(2), and two equivalent Gd(1) atoms to form distorted OBa2Gd3 trigonal bipyramids that share corners with two equivalent O(4)Ba2Gd3 square pyramids,  an edgeedge with one O(4)Ba2Gd3 square pyramid, edges with two equivalent O(6)Ba2Gd3 trigonal bipyramids, and edges with two equivalent O(5)Sr2Gd3 trigonal bipyramids. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to two equivalent Ba(1), one Gd(1), and two equivalent Gd(4) atoms. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to two equivalent Sr(1), one Gd(2), and two equivalent Gd(3) atoms.
BaSrGd4O8 crystallizes in the orthorhombic Pmc2_1 space group. Ba(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(4), two equivalent O(6), and two equivalent O(7) atoms. Both Ba(1)-O(2) bond lengths are 2.88 Å. Both Ba(1)-O(4) bond lengths are 2.74 Å. Both Ba(1)-O(6) bond lengths are 2.75 Å. There is one shorter (2.81 Å) and one longer (3.03 Å) Ba(1)-O(7) bond length. Sr(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), two equivalent O(5), and two equivalent O(8) atoms. Both Sr(1)-O(1) bond lengths are 2.84 Å. Both Sr(1)-O(3) bond lengths are 2.65 Å. Both Sr(1)-O(5) bond lengths are 2.69 Å. There is one shorter (2.74 Å) and one longer (3.10 Å) Sr(1)-O(8) bond length. There are four inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one O(5), one O(7), two equivalent O(2), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing GdO6 octahedra. The corner-sharing octahedral tilt angles range from 50-62°. The Gd(1)-O(5) bond length is 2.33 Å. The Gd(1)-O(7) bond length is 2.34 Å. Both Gd(1)-O(2) bond lengths are 2.34 Å. Both Gd(1)-O(6) bond lengths are 2.36 Å. In the second Gd site, Gd(2) is bonded to one O(6), one O(8), two equivalent O(1), and two equivalent O(5) atoms to form a mixture of corner and edge-sharing GdO6 octahedra. The corner-sharing octahedral tilt angles range from 51-62°. The Gd(2)-O(6) bond length is 2.32 Å. The Gd(2)-O(8) bond length is 2.27 Å. Both Gd(2)-O(1) bond lengths are 2.37 Å. Both Gd(2)-O(5) bond lengths are 2.39 Å. In the third Gd site, Gd(3) is bonded to one O(1), one O(3), two equivalent O(4), and two equivalent O(8) atoms to form a mixture of corner and edge-sharing GdO6 octahedra. The corner-sharing octahedral tilt angles range from 51-62°. The Gd(3)-O(1) bond length is 2.33 Å. The Gd(3)-O(3) bond length is 2.36 Å. Both Gd(3)-O(4) bond lengths are 2.40 Å. Both Gd(3)-O(8) bond lengths are 2.26 Å. In the fourth Gd site, Gd(4) is bonded to one O(2), one O(4), two equivalent O(3), and two equivalent O(7) atoms to form a mixture of corner and edge-sharing GdO6 octahedra. The corner-sharing octahedral tilt angles range from 50-62°. The Gd(4)-O(2) bond length is 2.30 Å. The Gd(4)-O(4) bond length is 2.34 Å. Both Gd(4)-O(3) bond lengths are 2.42 Å. Both Gd(4)-O(7) bond lengths are 2.28 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Sr(1), one Gd(3), and two equivalent Gd(2) atoms. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Ba(1), one Gd(4), and two equivalent Gd(1) atoms. In the third O site, O(3) is bonded to two equivalent Sr(1), one Gd(3), and two equivalent Gd(4) atoms to form OSr2Gd3 square pyramids that share corners with two equivalent O(5)Sr2Gd3 trigonal bipyramids, edges with two equivalent O(4)Ba2Gd3 square pyramids, edges with two equivalent O(3)Sr2Gd3 square pyramids, and  an edgeedge with one O(5)Sr2Gd3 trigonal bipyramid. In the fourth O site, O(4) is bonded to two equivalent Ba(1), one Gd(4), and two equivalent Gd(3) atoms to form OBa2Gd3 square pyramids that share corners with two equivalent O(6)Ba2Gd3 trigonal bipyramids, edges with two equivalent O(4)Ba2Gd3 square pyramids, edges with two equivalent O(3)Sr2Gd3 square pyramids, and  an edgeedge with one O(6)Ba2Gd3 trigonal bipyramid. In the fifth O site, O(5) is bonded to two equivalent Sr(1), one Gd(1), and two equivalent Gd(2) atoms to form distorted OSr2Gd3 trigonal bipyramids that share corners with two equivalent O(3)Sr2Gd3 square pyramids,  an edgeedge with one O(3)Sr2Gd3 square pyramid, edges with two equivalent O(6)Ba2Gd3 trigonal bipyramids, and edges with two equivalent O(5)Sr2Gd3 trigonal bipyramids. In the sixth O site, O(6) is bonded to two equivalent Ba(1), one Gd(2), and two equivalent Gd(1) atoms to form distorted OBa2Gd3 trigonal bipyramids that share corners with two equivalent O(4)Ba2Gd3 square pyramids,  an edgeedge with one O(4)Ba2Gd3 square pyramid, edges with two equivalent O(6)Ba2Gd3 trigonal bipyramids, and edges with two equivalent O(5)Sr2Gd3 trigonal bipyramids. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to two equivalent Ba(1), one Gd(1), and two equivalent Gd(4) atoms. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to two equivalent Sr(1), one Gd(2), and two equivalent Gd(3) atoms.