Sr3CaI8 is Fluorite-derived structured and crystallizes in the monoclinic Cm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a body-centered cubic geometry to one I(1), one I(3), one I(5), one I(6), two equivalent I(2), and two equivalent I(4) atoms. In the second Sr site, Sr(2) is bonded in a body-centered cubic geometry to one I(1), one I(3), one I(5), one I(6), two equivalent I(2), and two equivalent I(4) atoms. Ca(1) is bonded in a body-centered cubic geometry to one I(1), one I(3), one I(5), one I(6), two equivalent I(2), and two equivalent I(4) atoms. There are six inequivalent I sites. In the first I site, I(1) is bonded to one Sr(2), two equivalent Sr(1), and one Ca(1) atom to form a mixture of corner and edge-sharing ISr3Ca tetrahedra. In the second I site, I(2) is bonded to one Sr(2), two equivalent Sr(1), and one Ca(1) atom to form a mixture of corner and edge-sharing ISr3Ca tetrahedra. In the third I site, I(3) is bonded to one Sr(2), two equivalent Sr(1), and one Ca(1) atom to form a mixture of corner and edge-sharing ISr3Ca tetrahedra. In the fourth I site, I(4) is bonded to one Sr(2), two equivalent Sr(1), and one Ca(1) atom to form a mixture of corner and edge-sharing ISr3Ca tetrahedra. In the fifth I site, I(5) is bonded to one Sr(2), two equivalent Sr(1), and one Ca(1) atom to form a mixture of corner and edge-sharing ISr3Ca tetrahedra. In the sixth I site, I(6) is bonded to one Sr(2), two equivalent Sr(1), and one Ca(1) atom to form a mixture of corner and edge-sharing ISr3Ca tetrahedra.
Sr3CaI8 is Fluorite-derived structured and crystallizes in the monoclinic Cm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a body-centered cubic geometry to one I(1), one I(3), one I(5), one I(6), two equivalent I(2), and two equivalent I(4) atoms. The Sr(1)-I(1) bond length is 3.46 Å. The Sr(1)-I(3) bond length is 3.49 Å. The Sr(1)-I(5) bond length is 3.49 Å. The Sr(1)-I(6) bond length is 3.48 Å. There is one shorter (3.48 Å) and one longer (3.51 Å) Sr(1)-I(2) bond length. There is one shorter (3.46 Å) and one longer (3.47 Å) Sr(1)-I(4) bond length. In the second Sr site, Sr(2) is bonded in a body-centered cubic geometry to one I(1), one I(3), one I(5), one I(6), two equivalent I(2), and two equivalent I(4) atoms. The Sr(2)-I(1) bond length is 3.49 Å. The Sr(2)-I(3) bond length is 3.47 Å. The Sr(2)-I(5) bond length is 3.47 Å. The Sr(2)-I(6) bond length is 3.49 Å. Both Sr(2)-I(2) bond lengths are 3.48 Å. Both Sr(2)-I(4) bond lengths are 3.48 Å. Ca(1) is bonded in a body-centered cubic geometry to one I(1), one I(3), one I(5), one I(6), two equivalent I(2), and two equivalent I(4) atoms. The Ca(1)-I(1) bond length is 3.44 Å. The Ca(1)-I(3) bond length is 3.42 Å. The Ca(1)-I(5) bond length is 3.43 Å. The Ca(1)-I(6) bond length is 3.34 Å. Both Ca(1)-I(2) bond lengths are 3.41 Å. Both Ca(1)-I(4) bond lengths are 3.43 Å. There are six inequivalent I sites. In the first I site, I(1) is bonded to one Sr(2), two equivalent Sr(1), and one Ca(1) atom to form a mixture of corner and edge-sharing ISr3Ca tetrahedra. In the second I site, I(2) is bonded to one Sr(2), two equivalent Sr(1), and one Ca(1) atom to form a mixture of corner and edge-sharing ISr3Ca tetrahedra. In the third I site, I(3) is bonded to one Sr(2), two equivalent Sr(1), and one Ca(1) atom to form a mixture of corner and edge-sharing ISr3Ca tetrahedra. In the fourth I site, I(4) is bonded to one Sr(2), two equivalent Sr(1), and one Ca(1) atom to form a mixture of corner and edge-sharing ISr3Ca tetrahedra. In the fifth I site, I(5) is bonded to one Sr(2), two equivalent Sr(1), and one Ca(1) atom to form a mixture of corner and edge-sharing ISr3Ca tetrahedra. In the sixth I site, I(6) is bonded to one Sr(2), two equivalent Sr(1), and one Ca(1) atom to form a mixture of corner and edge-sharing ISr3Ca tetrahedra.