BaSr3(ZrSe3)4 crystallizes in the monoclinic Pm space group. Ba(1) is bonded in a 9-coordinate geometry to one Se(2), one Se(5), one Se(6), two equivalent Se(11), two equivalent Se(12), and two equivalent Se(4) atoms. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one Se(1), one Se(5), two equivalent Se(11), two equivalent Se(12), and two equivalent Se(3) atoms. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to one Se(4), one Se(8), two equivalent Se(10), two equivalent Se(2), and two equivalent Se(9) atoms. In the third Sr site, Sr(3) is bonded in a 8-coordinate geometry to one Se(3), one Se(7), two equivalent Se(1), two equivalent Se(10), and two equivalent Se(9) atoms. There are four inequivalent Zr sites. In the first Zr site, Zr(1) is bonded to one Se(5), one Se(9), two equivalent Se(4), and two equivalent Se(7) atoms to form edge-sharing ZrSe6 octahedra. In the second Zr site, Zr(2) is bonded to one Se(10), one Se(6), two equivalent Se(3), and two equivalent Se(8) atoms to form edge-sharing ZrSe6 octahedra. In the third Zr site, Zr(3) is bonded to one Se(11), one Se(7), two equivalent Se(2), and two equivalent Se(5) atoms to form edge-sharing ZrSe6 octahedra. In the fourth Zr site, Zr(4) is bonded to one Se(12), one Se(8), two equivalent Se(1), and two equivalent Se(6) atoms to form edge-sharing ZrSe6 octahedra. There are twelve inequivalent Se sites. In the first Se site, Se(1) is bonded in a 5-coordinate geometry to one Sr(1), two equivalent Sr(3), and two equivalent Zr(4) atoms. In the second Se site, Se(2) is bonded to one Ba(1), two equivalent Sr(2), and two equivalent Zr(3) atoms to form distorted SeBaSr2Zr2 trigonal bipyramids that share corners with two equivalent Se(12)Ba2Sr2Zr square pyramids, corners with two equivalent Se(10)Sr4Zr square pyramids, corners with two equivalent Se(9)Sr4Zr square pyramids,  an edgeedge with one Se(10)Sr4Zr square pyramid,  an edgeedge with one Se(9)Sr4Zr square pyramid, edges with two equivalent Se(11)Ba2Sr2Zr square pyramids, edges with two equivalent Se(4)Ba2SrZr2 trigonal bipyramids, and edges with two equivalent Se(2)BaSr2Zr2 trigonal bipyramids. In the third Se site, Se(3) is bonded to one Sr(3), two equivalent Sr(1), and two equivalent Zr(2) atoms to form distorted SeSr3Zr2 trigonal bipyramids that share corners with two equivalent Se(11)Ba2Sr2Zr square pyramids, corners with two equivalent Se(12)Ba2Sr2Zr square pyramids, corners with two equivalent Se(9)Sr4Zr square pyramids,  an edgeedge with one Se(11)Ba2Sr2Zr square pyramid,  an edgeedge with one Se(12)Ba2Sr2Zr square pyramid, edges with two equivalent Se(10)Sr4Zr square pyramids, and edges with two equivalent Se(3)Sr3Zr2 trigonal bipyramids. In the fourth Se site, Se(4) is bonded to two equivalent Ba(1), one Sr(2), and two equivalent Zr(1) atoms to form distorted SeBa2SrZr2 trigonal bipyramids that share corners with two equivalent Se(11)Ba2Sr2Zr square pyramids, corners with two equivalent Se(12)Ba2Sr2Zr square pyramids, corners with two equivalent Se(10)Sr4Zr square pyramids,  an edgeedge with one Se(11)Ba2Sr2Zr square pyramid,  an edgeedge with one Se(12)Ba2Sr2Zr square pyramid, edges with two equivalent Se(9)Sr4Zr square pyramids, edges with two equivalent Se(4)Ba2SrZr2 trigonal bipyramids, and edges with two equivalent Se(2)BaSr2Zr2 trigonal bipyramids. In the fifth Se site, Se(5) is bonded in a 5-coordinate geometry to one Ba(1), one Sr(1), one Zr(1), and two equivalent Zr(3) atoms. In the sixth Se site, Se(6) is bonded in a distorted rectangular see-saw-like geometry to one Ba(1), one Zr(2), and two equivalent Zr(4) atoms. In the seventh Se site, Se(7) is bonded in a distorted rectangular see-saw-like geometry to one Sr(3), one Zr(3), and two equivalent Zr(1) atoms. In the eighth Se site, Se(8) is bonded in a distorted rectangular see-saw-like geometry to one Sr(2), one Zr(4), and two equivalent Zr(2) atoms. In the ninth Se site, Se(9) is bonded to two equivalent Sr(2), two equivalent Sr(3), and one Zr(1) atom to form distorted SeSr4Zr square pyramids that share corners with four equivalent Se(10)Sr4Zr square pyramids, corners with two equivalent Se(2)BaSr2Zr2 trigonal bipyramids, corners with two equivalent Se(3)Sr3Zr2 trigonal bipyramids, edges with two equivalent Se(10)Sr4Zr square pyramids, edges with two equivalent Se(9)Sr4Zr square pyramids,  an edgeedge with one Se(2)BaSr2Zr2 trigonal bipyramid, and edges with two equivalent Se(4)Ba2SrZr2 trigonal bipyramids. In the tenth Se site, Se(10) is bonded to two equivalent Sr(2), two equivalent Sr(3), and one Zr(2) atom to form distorted SeSr4Zr square pyramids that share corners with four equivalent Se(9)Sr4Zr square pyramids, corners with two equivalent Se(4)Ba2SrZr2 trigonal bipyramids, corners with two equivalent Se(2)BaSr2Zr2 trigonal bipyramids, edges with two equivalent Se(10)Sr4Zr square pyramids, edges with two equivalent Se(9)Sr4Zr square pyramids,  an edgeedge with one Se(2)BaSr2Zr2 trigonal bipyramid, and edges with two equivalent Se(3)Sr3Zr2 trigonal bipyramids. In the eleventh Se site, Se(11) is bonded to two equivalent Ba(1), two equivalent Sr(1), and one Zr(3) atom to form distorted SeBa2Sr2Zr square pyramids that share corners with four equivalent Se(12)Ba2Sr2Zr square pyramids, corners with two equivalent Se(4)Ba2SrZr2 trigonal bipyramids, corners with two equivalent Se(3)Sr3Zr2 trigonal bipyramids, edges with two equivalent Se(11)Ba2Sr2Zr square pyramids, edges with two equivalent Se(12)Ba2Sr2Zr square pyramids,  an edgeedge with one Se(4)Ba2SrZr2 trigonal bipyramid,  an edgeedge with one Se(3)Sr3Zr2 trigonal bipyramid, and edges with two equivalent Se(2)BaSr2Zr2 trigonal bipyramids. In the twelfth Se site, Se(12) is bonded to two equivalent Ba(1), two equivalent Sr(1), and one Zr(4) atom to form distorted SeBa2Sr2Zr square pyramids that share corners with four equivalent Se(11)Ba2Sr2Zr square pyramids, corners with two equivalent Se(4)Ba2SrZr2 trigonal bipyramids, corners with two equivalent Se(2)BaSr2Zr2 trigonal bipyramids, corners with two equivalent Se(3)Sr3Zr2 trigonal bipyramids, edges with two equivalent Se(11)Ba2Sr2Zr square pyramids, edges with two equivalent Se(12)Ba2Sr2Zr square pyramids,  an edgeedge with one Se(4)Ba2SrZr2 trigonal bipyramid, and  an edgeedge with one Se(3)Sr3Zr2 trigonal bipyramid.
BaSr3(ZrSe3)4 crystallizes in the monoclinic Pm space group. Ba(1) is bonded in a 9-coordinate geometry to one Se(2), one Se(5), one Se(6), two equivalent Se(11), two equivalent Se(12), and two equivalent Se(4) atoms. The Ba(1)-Se(2) bond length is 3.50 Å. The Ba(1)-Se(5) bond length is 3.83 Å. The Ba(1)-Se(6) bond length is 3.32 Å. Both Ba(1)-Se(11) bond lengths are 3.36 Å. Both Ba(1)-Se(12) bond lengths are 3.35 Å. Both Ba(1)-Se(4) bond lengths are 3.35 Å. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one Se(1), one Se(5), two equivalent Se(11), two equivalent Se(12), and two equivalent Se(3) atoms. The Sr(1)-Se(1) bond length is 3.46 Å. The Sr(1)-Se(5) bond length is 3.32 Å. Both Sr(1)-Se(11) bond lengths are 3.20 Å. Both Sr(1)-Se(12) bond lengths are 3.16 Å. Both Sr(1)-Se(3) bond lengths are 3.29 Å. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to one Se(4), one Se(8), two equivalent Se(10), two equivalent Se(2), and two equivalent Se(9) atoms. The Sr(2)-Se(4) bond length is 3.39 Å. The Sr(2)-Se(8) bond length is 3.25 Å. Both Sr(2)-Se(10) bond lengths are 3.27 Å. Both Sr(2)-Se(2) bond lengths are 3.31 Å. Both Sr(2)-Se(9) bond lengths are 3.23 Å. In the third Sr site, Sr(3) is bonded in a 8-coordinate geometry to one Se(3), one Se(7), two equivalent Se(1), two equivalent Se(10), and two equivalent Se(9) atoms. The Sr(3)-Se(3) bond length is 3.46 Å. The Sr(3)-Se(7) bond length is 3.26 Å. Both Sr(3)-Se(1) bond lengths are 3.28 Å. Both Sr(3)-Se(10) bond lengths are 3.23 Å. Both Sr(3)-Se(9) bond lengths are 3.26 Å. There are four inequivalent Zr sites. In the first Zr site, Zr(1) is bonded to one Se(5), one Se(9), two equivalent Se(4), and two equivalent Se(7) atoms to form edge-sharing ZrSe6 octahedra. The Zr(1)-Se(5) bond length is 2.79 Å. The Zr(1)-Se(9) bond length is 2.61 Å. Both Zr(1)-Se(4) bond lengths are 2.72 Å. Both Zr(1)-Se(7) bond lengths are 2.74 Å. In the second Zr site, Zr(2) is bonded to one Se(10), one Se(6), two equivalent Se(3), and two equivalent Se(8) atoms to form edge-sharing ZrSe6 octahedra. The Zr(2)-Se(10) bond length is 2.61 Å. The Zr(2)-Se(6) bond length is 2.78 Å. Both Zr(2)-Se(3) bond lengths are 2.73 Å. Both Zr(2)-Se(8) bond lengths are 2.75 Å. In the third Zr site, Zr(3) is bonded to one Se(11), one Se(7), two equivalent Se(2), and two equivalent Se(5) atoms to form edge-sharing ZrSe6 octahedra. The Zr(3)-Se(11) bond length is 2.60 Å. The Zr(3)-Se(7) bond length is 2.78 Å. Both Zr(3)-Se(2) bond lengths are 2.73 Å. Both Zr(3)-Se(5) bond lengths are 2.75 Å. In the fourth Zr site, Zr(4) is bonded to one Se(12), one Se(8), two equivalent Se(1), and two equivalent Se(6) atoms to form edge-sharing ZrSe6 octahedra. The Zr(4)-Se(12) bond length is 2.61 Å. The Zr(4)-Se(8) bond length is 2.78 Å. Both Zr(4)-Se(1) bond lengths are 2.73 Å. Both Zr(4)-Se(6) bond lengths are 2.76 Å. There are twelve inequivalent Se sites. In the first Se site, Se(1) is bonded in a 5-coordinate geometry to one Sr(1), two equivalent Sr(3), and two equivalent Zr(4) atoms. In the second Se site, Se(2) is bonded to one Ba(1), two equivalent Sr(2), and two equivalent Zr(3) atoms to form distorted SeBaSr2Zr2 trigonal bipyramids that share corners with two equivalent Se(12)Ba2Sr2Zr square pyramids, corners with two equivalent Se(10)Sr4Zr square pyramids, corners with two equivalent Se(9)Sr4Zr square pyramids,  an edgeedge with one Se(10)Sr4Zr square pyramid,  an edgeedge with one Se(9)Sr4Zr square pyramid, edges with two equivalent Se(11)Ba2Sr2Zr square pyramids, edges with two equivalent Se(4)Ba2SrZr2 trigonal bipyramids, and edges with two equivalent Se(2)BaSr2Zr2 trigonal bipyramids. In the third Se site, Se(3) is bonded to one Sr(3), two equivalent Sr(1), and two equivalent Zr(2) atoms to form distorted SeSr3Zr2 trigonal bipyramids that share corners with two equivalent Se(11)Ba2Sr2Zr square pyramids, corners with two equivalent Se(12)Ba2Sr2Zr square pyramids, corners with two equivalent Se(9)Sr4Zr square pyramids,  an edgeedge with one Se(11)Ba2Sr2Zr square pyramid,  an edgeedge with one Se(12)Ba2Sr2Zr square pyramid, edges with two equivalent Se(10)Sr4Zr square pyramids, and edges with two equivalent Se(3)Sr3Zr2 trigonal bipyramids. In the fourth Se site, Se(4) is bonded to two equivalent Ba(1), one Sr(2), and two equivalent Zr(1) atoms to form distorted SeBa2SrZr2 trigonal bipyramids that share corners with two equivalent Se(11)Ba2Sr2Zr square pyramids, corners with two equivalent Se(12)Ba2Sr2Zr square pyramids, corners with two equivalent Se(10)Sr4Zr square pyramids,  an edgeedge with one Se(11)Ba2Sr2Zr square pyramid,  an edgeedge with one Se(12)Ba2Sr2Zr square pyramid, edges with two equivalent Se(9)Sr4Zr square pyramids, edges with two equivalent Se(4)Ba2SrZr2 trigonal bipyramids, and edges with two equivalent Se(2)BaSr2Zr2 trigonal bipyramids. In the fifth Se site, Se(5) is bonded in a 5-coordinate geometry to one Ba(1), one Sr(1), one Zr(1), and two equivalent Zr(3) atoms. In the sixth Se site, Se(6) is bonded in a distorted rectangular see-saw-like geometry to one Ba(1), one Zr(2), and two equivalent Zr(4) atoms. In the seventh Se site, Se(7) is bonded in a distorted rectangular see-saw-like geometry to one Sr(3), one Zr(3), and two equivalent Zr(1) atoms. In the eighth Se site, Se(8) is bonded in a distorted rectangular see-saw-like geometry to one Sr(2), one Zr(4), and two equivalent Zr(2) atoms. In the ninth Se site, Se(9) is bonded to two equivalent Sr(2), two equivalent Sr(3), and one Zr(1) atom to form distorted SeSr4Zr square pyramids that share corners with four equivalent Se(10)Sr4Zr square pyramids, corners with two equivalent Se(2)BaSr2Zr2 trigonal bipyramids, corners with two equivalent Se(3)Sr3Zr2 trigonal bipyramids, edges with two equivalent Se(10)Sr4Zr square pyramids, edges with two equivalent Se(9)Sr4Zr square pyramids,  an edgeedge with one Se(2)BaSr2Zr2 trigonal bipyramid, and edges with two equivalent Se(4)Ba2SrZr2 trigonal bipyramids. In the tenth Se site, Se(10) is bonded to two equivalent Sr(2), two equivalent Sr(3), and one Zr(2) atom to form distorted SeSr4Zr square pyramids that share corners with four equivalent Se(9)Sr4Zr square pyramids, corners with two equivalent Se(4)Ba2SrZr2 trigonal bipyramids, corners with two equivalent Se(2)BaSr2Zr2 trigonal bipyramids, edges with two equivalent Se(10)Sr4Zr square pyramids, edges with two equivalent Se(9)Sr4Zr square pyramids,  an edgeedge with one Se(2)BaSr2Zr2 trigonal bipyramid, and edges with two equivalent Se(3)Sr3Zr2 trigonal bipyramids. In the eleventh Se site, Se(11) is bonded to two equivalent Ba(1), two equivalent Sr(1), and one Zr(3) atom to form distorted SeBa2Sr2Zr square pyramids that share corners with four equivalent Se(12)Ba2Sr2Zr square pyramids, corners with two equivalent Se(4)Ba2SrZr2 trigonal bipyramids, corners with two equivalent Se(3)Sr3Zr2 trigonal bipyramids, edges with two equivalent Se(11)Ba2Sr2Zr square pyramids, edges with two equivalent Se(12)Ba2Sr2Zr square pyramids,  an edgeedge with one Se(4)Ba2SrZr2 trigonal bipyramid,  an edgeedge with one Se(3)Sr3Zr2 trigonal bipyramid, and edges with two equivalent Se(2)BaSr2Zr2 trigonal bipyramids. In the twelfth Se site, Se(12) is bonded to two equivalent Ba(1), two equivalent Sr(1), and one Zr(4) atom to form distorted SeBa2Sr2Zr square pyramids that share corners with four equivalent Se(11)Ba2Sr2Zr square pyramids, corners with two equivalent Se(4)Ba2SrZr2 trigonal bipyramids, corners with two equivalent Se(2)BaSr2Zr2 trigonal bipyramids, corners with two equivalent Se(3)Sr3Zr2 trigonal bipyramids, edges with two equivalent Se(11)Ba2Sr2Zr square pyramids, edges with two equivalent Se(12)Ba2Sr2Zr square pyramids,  an edgeedge with one Se(4)Ba2SrZr2 trigonal bipyramid, and  an edgeedge with one Se(3)Sr3Zr2 trigonal bipyramid.