Sr2YI7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to one I(1), one I(3), one I(4), one I(5), one I(7), two equivalent I(2), and two equivalent I(6) atoms. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to one I(1), one I(2), one I(3), one I(4), one I(5), one I(6), and two equivalent I(7) atoms. Y(1) is bonded in a distorted pentagonal bipyramidal geometry to one I(1), one I(2), one I(3), one I(4), one I(5), one I(6), and one I(7) atom. There are seven inequivalent I sites. In the first I site, I(1) is bonded in a trigonal non-coplanar geometry to one Sr(1), one Sr(2), and one Y(1) atom. In the second I site, I(2) is bonded to one Sr(2), two equivalent Sr(1), and one Y(1) atom to form a mixture of distorted edge and corner-sharing ISr3Y tetrahedra. In the third I site, I(3) is bonded in a trigonal non-coplanar geometry to one Sr(1), one Sr(2), and one Y(1) atom. In the fourth I site, I(4) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(2), and one Y(1) atom. In the fifth I site, I(5) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(2), and one Y(1) atom. In the sixth I site, I(6) is bonded to one Sr(2), two equivalent Sr(1), and one Y(1) atom to form a mixture of edge and corner-sharing ISr3Y tetrahedra. In the seventh I site, I(7) is bonded to one Sr(1), two equivalent Sr(2), and one Y(1) atom to form a mixture of edge and corner-sharing ISr3Y tetrahedra.
Sr2YI7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to one I(1), one I(3), one I(4), one I(5), one I(7), two equivalent I(2), and two equivalent I(6) atoms. The Sr(1)-I(1) bond length is 3.52 Å. The Sr(1)-I(3) bond length is 3.48 Å. The Sr(1)-I(4) bond length is 3.85 Å. The Sr(1)-I(5) bond length is 3.47 Å. The Sr(1)-I(7) bond length is 3.60 Å. There is one shorter (3.73 Å) and one longer (3.76 Å) Sr(1)-I(2) bond length. There is one shorter (3.52 Å) and one longer (3.54 Å) Sr(1)-I(6) bond length. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to one I(1), one I(2), one I(3), one I(4), one I(5), one I(6), and two equivalent I(7) atoms. The Sr(2)-I(1) bond length is 3.55 Å. The Sr(2)-I(2) bond length is 3.78 Å. The Sr(2)-I(3) bond length is 3.47 Å. The Sr(2)-I(4) bond length is 3.46 Å. The Sr(2)-I(5) bond length is 3.66 Å. The Sr(2)-I(6) bond length is 3.50 Å. There is one shorter (3.46 Å) and one longer (3.47 Å) Sr(2)-I(7) bond length. Y(1) is bonded in a distorted pentagonal bipyramidal geometry to one I(1), one I(2), one I(3), one I(4), one I(5), one I(6), and one I(7) atom. The Y(1)-I(1) bond length is 3.13 Å. The Y(1)-I(2) bond length is 3.11 Å. The Y(1)-I(3) bond length is 3.18 Å. The Y(1)-I(4) bond length is 3.08 Å. The Y(1)-I(5) bond length is 3.06 Å. The Y(1)-I(6) bond length is 3.28 Å. The Y(1)-I(7) bond length is 3.18 Å. There are seven inequivalent I sites. In the first I site, I(1) is bonded in a trigonal non-coplanar geometry to one Sr(1), one Sr(2), and one Y(1) atom. In the second I site, I(2) is bonded to one Sr(2), two equivalent Sr(1), and one Y(1) atom to form a mixture of distorted edge and corner-sharing ISr3Y tetrahedra. In the third I site, I(3) is bonded in a trigonal non-coplanar geometry to one Sr(1), one Sr(2), and one Y(1) atom. In the fourth I site, I(4) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(2), and one Y(1) atom. In the fifth I site, I(5) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(2), and one Y(1) atom. In the sixth I site, I(6) is bonded to one Sr(2), two equivalent Sr(1), and one Y(1) atom to form a mixture of edge and corner-sharing ISr3Y tetrahedra. In the seventh I site, I(7) is bonded to one Sr(1), two equivalent Sr(2), and one Y(1) atom to form a mixture of edge and corner-sharing ISr3Y tetrahedra.