SrSn3Sb4 crystallizes in the orthorhombic Pnma space group. Sr(1) is bonded in a 9-coordinate geometry to one Sn(1), one Sb(3), two equivalent Sb(2), two equivalent Sb(4), and three equivalent Sb(1) atoms. There are three inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a rectangular see-saw-like geometry to one Sr(1), one Sb(3), and two equivalent Sb(2) atoms. In the second Sn site, Sn(2) is bonded in a distorted T-shaped geometry to one Sb(1) and two equivalent Sb(4) atoms. In the third Sn site, Sn(3) is bonded to one Sb(2), one Sb(4), and two equivalent Sb(3) atoms to form corner-sharing SnSb4 tetrahedra. There are four inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 6-coordinate geometry to three equivalent Sr(1), one Sn(2), and two equivalent Sb(1) atoms. In the second Sb site, Sb(2) is bonded to two equivalent Sr(1), one Sn(3), and two equivalent Sn(1) atoms to form distorted SbSr2Sn3 trigonal bipyramids that share corners with three equivalent Sb(4)Sr2Sn3 trigonal bipyramids, corners with two equivalent Sb(3)SrSn3 trigonal pyramids,  an edgeedge with one Sb(4)Sr2Sn3 trigonal bipyramid, edges with two equivalent Sb(2)Sr2Sn3 trigonal bipyramids, and edges with two equivalent Sb(3)SrSn3 trigonal pyramids. In the third Sb site, Sb(3) is bonded to one Sr(1), one Sn(1), and two equivalent Sn(3) atoms to form SbSrSn3 trigonal pyramids that share corners with two equivalent Sb(2)Sr2Sn3 trigonal bipyramids, corners with four equivalent Sb(4)Sr2Sn3 trigonal bipyramids, corners with two equivalent Sb(3)SrSn3 trigonal pyramids, and edges with two equivalent Sb(2)Sr2Sn3 trigonal bipyramids. In the fourth Sb site, Sb(4) is bonded to two equivalent Sr(1), one Sn(3), and two equivalent Sn(2) atoms to form distorted SbSr2Sn3 trigonal bipyramids that share corners with three equivalent Sb(2)Sr2Sn3 trigonal bipyramids, corners with four equivalent Sb(3)SrSn3 trigonal pyramids,  an edgeedge with one Sb(2)Sr2Sn3 trigonal bipyramid, and edges with two equivalent Sb(4)Sr2Sn3 trigonal bipyramids.
SrSn3Sb4 crystallizes in the orthorhombic Pnma space group. Sr(1) is bonded in a 9-coordinate geometry to one Sn(1), one Sb(3), two equivalent Sb(2), two equivalent Sb(4), and three equivalent Sb(1) atoms. The Sr(1)-Sn(1) bond length is 3.56 Å. The Sr(1)-Sb(3) bond length is 3.59 Å. Both Sr(1)-Sb(2) bond lengths are 3.40 Å. Both Sr(1)-Sb(4) bond lengths are 3.40 Å. There are two shorter (3.53 Å) and one longer (3.73 Å) Sr(1)-Sb(1) bond length. There are three inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a rectangular see-saw-like geometry to one Sr(1), one Sb(3), and two equivalent Sb(2) atoms. The Sn(1)-Sb(3) bond length is 2.95 Å. Both Sn(1)-Sb(2) bond lengths are 2.93 Å. In the second Sn site, Sn(2) is bonded in a distorted T-shaped geometry to one Sb(1) and two equivalent Sb(4) atoms. The Sn(2)-Sb(1) bond length is 2.99 Å. Both Sn(2)-Sb(4) bond lengths are 2.95 Å. In the third Sn site, Sn(3) is bonded to one Sb(2), one Sb(4), and two equivalent Sb(3) atoms to form corner-sharing SnSb4 tetrahedra. The Sn(3)-Sb(2) bond length is 2.83 Å. The Sn(3)-Sb(4) bond length is 2.82 Å. Both Sn(3)-Sb(3) bond lengths are 2.84 Å. There are four inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 6-coordinate geometry to three equivalent Sr(1), one Sn(2), and two equivalent Sb(1) atoms. Both Sb(1)-Sb(1) bond lengths are 2.94 Å. In the second Sb site, Sb(2) is bonded to two equivalent Sr(1), one Sn(3), and two equivalent Sn(1) atoms to form distorted SbSr2Sn3 trigonal bipyramids that share corners with three equivalent Sb(4)Sr2Sn3 trigonal bipyramids, corners with two equivalent Sb(3)SrSn3 trigonal pyramids,  an edgeedge with one Sb(4)Sr2Sn3 trigonal bipyramid, edges with two equivalent Sb(2)Sr2Sn3 trigonal bipyramids, and edges with two equivalent Sb(3)SrSn3 trigonal pyramids. In the third Sb site, Sb(3) is bonded to one Sr(1), one Sn(1), and two equivalent Sn(3) atoms to form SbSrSn3 trigonal pyramids that share corners with two equivalent Sb(2)Sr2Sn3 trigonal bipyramids, corners with four equivalent Sb(4)Sr2Sn3 trigonal bipyramids, corners with two equivalent Sb(3)SrSn3 trigonal pyramids, and edges with two equivalent Sb(2)Sr2Sn3 trigonal bipyramids. In the fourth Sb site, Sb(4) is bonded to two equivalent Sr(1), one Sn(3), and two equivalent Sn(2) atoms to form distorted SbSr2Sn3 trigonal bipyramids that share corners with three equivalent Sb(2)Sr2Sn3 trigonal bipyramids, corners with four equivalent Sb(3)SrSn3 trigonal pyramids,  an edgeedge with one Sb(2)Sr2Sn3 trigonal bipyramid, and edges with two equivalent Sb(4)Sr2Sn3 trigonal bipyramids.