SrCa2I6 is trigonal omega-derived structured and crystallizes in the monoclinic P2_1/c space group. Sr(1) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(3) atoms to form SrI6 octahedra that share corners with four equivalent Ca(1)I6 pentagonal pyramids and edges with four equivalent Ca(1)I6 pentagonal pyramids. Ca(1) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(3) atoms to form distorted CaI6 pentagonal pyramids that share corners with two equivalent Sr(1)I6 octahedra, corners with two equivalent Ca(1)I6 pentagonal pyramids, edges with two equivalent Sr(1)I6 octahedra, and edges with two equivalent Ca(1)I6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 47-75°. There are three inequivalent I sites. In the first I site, I(1) is bonded in a T-shaped geometry to one Sr(1) and two equivalent Ca(1) atoms. In the second I site, I(2) is bonded in a distorted T-shaped geometry to one Sr(1) and two equivalent Ca(1) atoms. In the third I site, I(3) is bonded in a T-shaped geometry to one Sr(1) and two equivalent Ca(1) atoms.
SrCa2I6 is trigonal omega-derived structured and crystallizes in the monoclinic P2_1/c space group. Sr(1) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(3) atoms to form SrI6 octahedra that share corners with four equivalent Ca(1)I6 pentagonal pyramids and edges with four equivalent Ca(1)I6 pentagonal pyramids. Both Sr(1)-I(1) bond lengths are 3.29 Å. Both Sr(1)-I(2) bond lengths are 3.22 Å. Both Sr(1)-I(3) bond lengths are 3.33 Å. Ca(1) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(3) atoms to form distorted CaI6 pentagonal pyramids that share corners with two equivalent Sr(1)I6 octahedra, corners with two equivalent Ca(1)I6 pentagonal pyramids, edges with two equivalent Sr(1)I6 octahedra, and edges with two equivalent Ca(1)I6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 47-75°. There is one shorter (3.19 Å) and one longer (3.21 Å) Ca(1)-I(1) bond length. There is one shorter (3.17 Å) and one longer (3.25 Å) Ca(1)-I(2) bond length. There is one shorter (3.22 Å) and one longer (3.29 Å) Ca(1)-I(3) bond length. There are three inequivalent I sites. In the first I site, I(1) is bonded in a T-shaped geometry to one Sr(1) and two equivalent Ca(1) atoms. In the second I site, I(2) is bonded in a distorted T-shaped geometry to one Sr(1) and two equivalent Ca(1) atoms. In the third I site, I(3) is bonded in a T-shaped geometry to one Sr(1) and two equivalent Ca(1) atoms.