BaSrSm4O8 crystallizes in the orthorhombic Pmc2_1 space group. Ba(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(4), two equivalent O(6), and two equivalent O(8) atoms. Sr(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(5), and two equivalent O(7) atoms. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to one O(1), one O(7), two equivalent O(6), and two equivalent O(8) atoms to form a mixture of edge and corner-sharing SmO6 octahedra. The corner-sharing octahedral tilt angles range from 51-64°. In the second Sm site, Sm(2) is bonded to one O(2), one O(8), two equivalent O(5), and two equivalent O(7) atoms to form a mixture of edge and corner-sharing SmO6 octahedra. The corner-sharing octahedral tilt angles range from 51-64°. In the third Sm site, Sm(3) is bonded to one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form a mixture of edge and corner-sharing SmO6 octahedra. The corner-sharing octahedral tilt angles range from 51-64°. In the fourth Sm site, Sm(4) is bonded to one O(4), one O(6), two equivalent O(1), and two equivalent O(3) atoms to form a mixture of edge and corner-sharing SmO6 octahedra. The corner-sharing octahedral tilt angles range from 51-64°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1), one Sm(1), and two equivalent Sm(4) atoms to form distorted OBa2Sm3 trigonal bipyramids that share corners with two equivalent O(4)Ba2Sm3 square pyramids, corners with two equivalent O(3)Sr2Sm3 square pyramids,  a cornercorner with one O(7)Sr2Sm3 trigonal bipyramid, corners with two equivalent O(8)Ba2Sm3 trigonal bipyramids, corners with four equivalent O(1)Ba2Sm3 trigonal bipyramids,  an edgeedge with one O(3)Sr2Sm3 square pyramid, edges with two equivalent O(4)Ba2Sm3 square pyramids, and edges with two equivalent O(8)Ba2Sm3 trigonal bipyramids. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Sr(1), one Sm(2), and two equivalent Sm(3) atoms. In the third O site, O(3) is bonded to two equivalent Sr(1), one Sm(3), and two equivalent Sm(4) atoms to form OSr2Sm3 square pyramids that share corners with two equivalent O(1)Ba2Sm3 trigonal bipyramids, corners with two equivalent O(7)Sr2Sm3 trigonal bipyramids, edges with two equivalent O(4)Ba2Sm3 square pyramids, edges with two equivalent O(3)Sr2Sm3 square pyramids,  an edgeedge with one O(1)Ba2Sm3 trigonal bipyramid, and  an edgeedge with one O(7)Sr2Sm3 trigonal bipyramid. In the fourth O site, O(4) is bonded to two equivalent Ba(1), one Sm(4), and two equivalent Sm(3) atoms to form OBa2Sm3 square pyramids that share corners with two equivalent O(1)Ba2Sm3 trigonal bipyramids, corners with two equivalent O(8)Ba2Sm3 trigonal bipyramids, edges with two equivalent O(4)Ba2Sm3 square pyramids, edges with two equivalent O(3)Sr2Sm3 square pyramids,  an edgeedge with one O(8)Ba2Sm3 trigonal bipyramid, and edges with two equivalent O(1)Ba2Sm3 trigonal bipyramids. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to two equivalent Sr(1), one Sm(3), and two equivalent Sm(2) atoms. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to two equivalent Ba(1), one Sm(4), and two equivalent Sm(1) atoms. In the seventh O site, O(7) is bonded to two equivalent Sr(1), one Sm(1), and two equivalent Sm(2) atoms to form distorted OSr2Sm3 trigonal bipyramids that share corners with two equivalent O(3)Sr2Sm3 square pyramids,  a cornercorner with one O(1)Ba2Sm3 trigonal bipyramid,  an edgeedge with one O(3)Sr2Sm3 square pyramid, edges with two equivalent O(8)Ba2Sm3 trigonal bipyramids, and edges with two equivalent O(7)Sr2Sm3 trigonal bipyramids. In the eighth O site, O(8) is bonded to two equivalent Ba(1), one Sm(2), and two equivalent Sm(1) atoms to form distorted OBa2Sm3 trigonal bipyramids that share corners with two equivalent O(4)Ba2Sm3 square pyramids, corners with two equivalent O(1)Ba2Sm3 trigonal bipyramids,  an edgeedge with one O(4)Ba2Sm3 square pyramid, edges with two equivalent O(1)Ba2Sm3 trigonal bipyramids, edges with two equivalent O(8)Ba2Sm3 trigonal bipyramids, and edges with two equivalent O(7)Sr2Sm3 trigonal bipyramids.
BaSrSm4O8 crystallizes in the orthorhombic Pmc2_1 space group. Ba(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(4), two equivalent O(6), and two equivalent O(8) atoms. There is one shorter (2.87 Å) and one longer (3.01 Å) Ba(1)-O(1) bond length. Both Ba(1)-O(4) bond lengths are 2.76 Å. Both Ba(1)-O(6) bond lengths are 2.89 Å. Both Ba(1)-O(8) bond lengths are 2.76 Å. Sr(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(5), and two equivalent O(7) atoms. There is one shorter (2.83 Å) and one longer (3.04 Å) Sr(1)-O(2) bond length. Both Sr(1)-O(3) bond lengths are 2.67 Å. Both Sr(1)-O(5) bond lengths are 2.83 Å. Both Sr(1)-O(7) bond lengths are 2.68 Å. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to one O(1), one O(7), two equivalent O(6), and two equivalent O(8) atoms to form a mixture of edge and corner-sharing SmO6 octahedra. The corner-sharing octahedral tilt angles range from 51-64°. The Sm(1)-O(1) bond length is 2.39 Å. The Sm(1)-O(7) bond length is 2.34 Å. Both Sm(1)-O(6) bond lengths are 2.37 Å. Both Sm(1)-O(8) bond lengths are 2.41 Å. In the second Sm site, Sm(2) is bonded to one O(2), one O(8), two equivalent O(5), and two equivalent O(7) atoms to form a mixture of edge and corner-sharing SmO6 octahedra. The corner-sharing octahedral tilt angles range from 51-64°. The Sm(2)-O(2) bond length is 2.30 Å. The Sm(2)-O(8) bond length is 2.33 Å. Both Sm(2)-O(5) bond lengths are 2.40 Å. Both Sm(2)-O(7) bond lengths are 2.45 Å. In the third Sm site, Sm(3) is bonded to one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form a mixture of edge and corner-sharing SmO6 octahedra. The corner-sharing octahedral tilt angles range from 51-64°. The Sm(3)-O(3) bond length is 2.41 Å. The Sm(3)-O(5) bond length is 2.36 Å. Both Sm(3)-O(2) bond lengths are 2.28 Å. Both Sm(3)-O(4) bond lengths are 2.45 Å. In the fourth Sm site, Sm(4) is bonded to one O(4), one O(6), two equivalent O(1), and two equivalent O(3) atoms to form a mixture of edge and corner-sharing SmO6 octahedra. The corner-sharing octahedral tilt angles range from 51-64°. The Sm(4)-O(4) bond length is 2.38 Å. The Sm(4)-O(6) bond length is 2.33 Å. Both Sm(4)-O(1) bond lengths are 2.30 Å. Both Sm(4)-O(3) bond lengths are 2.48 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1), one Sm(1), and two equivalent Sm(4) atoms to form distorted OBa2Sm3 trigonal bipyramids that share corners with two equivalent O(4)Ba2Sm3 square pyramids, corners with two equivalent O(3)Sr2Sm3 square pyramids,  a cornercorner with one O(7)Sr2Sm3 trigonal bipyramid, corners with two equivalent O(8)Ba2Sm3 trigonal bipyramids, corners with four equivalent O(1)Ba2Sm3 trigonal bipyramids,  an edgeedge with one O(3)Sr2Sm3 square pyramid, edges with two equivalent O(4)Ba2Sm3 square pyramids, and edges with two equivalent O(8)Ba2Sm3 trigonal bipyramids. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Sr(1), one Sm(2), and two equivalent Sm(3) atoms. In the third O site, O(3) is bonded to two equivalent Sr(1), one Sm(3), and two equivalent Sm(4) atoms to form OSr2Sm3 square pyramids that share corners with two equivalent O(1)Ba2Sm3 trigonal bipyramids, corners with two equivalent O(7)Sr2Sm3 trigonal bipyramids, edges with two equivalent O(4)Ba2Sm3 square pyramids, edges with two equivalent O(3)Sr2Sm3 square pyramids,  an edgeedge with one O(1)Ba2Sm3 trigonal bipyramid, and  an edgeedge with one O(7)Sr2Sm3 trigonal bipyramid. In the fourth O site, O(4) is bonded to two equivalent Ba(1), one Sm(4), and two equivalent Sm(3) atoms to form OBa2Sm3 square pyramids that share corners with two equivalent O(1)Ba2Sm3 trigonal bipyramids, corners with two equivalent O(8)Ba2Sm3 trigonal bipyramids, edges with two equivalent O(4)Ba2Sm3 square pyramids, edges with two equivalent O(3)Sr2Sm3 square pyramids,  an edgeedge with one O(8)Ba2Sm3 trigonal bipyramid, and edges with two equivalent O(1)Ba2Sm3 trigonal bipyramids. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to two equivalent Sr(1), one Sm(3), and two equivalent Sm(2) atoms. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to two equivalent Ba(1), one Sm(4), and two equivalent Sm(1) atoms. In the seventh O site, O(7) is bonded to two equivalent Sr(1), one Sm(1), and two equivalent Sm(2) atoms to form distorted OSr2Sm3 trigonal bipyramids that share corners with two equivalent O(3)Sr2Sm3 square pyramids,  a cornercorner with one O(1)Ba2Sm3 trigonal bipyramid,  an edgeedge with one O(3)Sr2Sm3 square pyramid, edges with two equivalent O(8)Ba2Sm3 trigonal bipyramids, and edges with two equivalent O(7)Sr2Sm3 trigonal bipyramids. In the eighth O site, O(8) is bonded to two equivalent Ba(1), one Sm(2), and two equivalent Sm(1) atoms to form distorted OBa2Sm3 trigonal bipyramids that share corners with two equivalent O(4)Ba2Sm3 square pyramids, corners with two equivalent O(1)Ba2Sm3 trigonal bipyramids,  an edgeedge with one O(4)Ba2Sm3 square pyramid, edges with two equivalent O(1)Ba2Sm3 trigonal bipyramids, edges with two equivalent O(8)Ba2Sm3 trigonal bipyramids, and edges with two equivalent O(7)Sr2Sm3 trigonal bipyramids.