Ba2CaI6 crystallizes in the monoclinic C2/c space group. Ba(1) is bonded in a 8-coordinate geometry to two equivalent I(1), two equivalent I(3), and four equivalent I(2) atoms. Ca(1) is bonded in a 8-coordinate geometry to two equivalent I(1), two equivalent I(2), and four equivalent I(3) atoms. There are three inequivalent I sites. In the first I site, I(1) is bonded in a distorted T-shaped geometry to two equivalent Ba(1) and one Ca(1) atom. In the second I site, I(2) is bonded to four equivalent Ba(1) and one Ca(1) atom to form distorted IBa4Ca square pyramids that share corners with four equivalent I(2)Ba4Ca square pyramids, corners with five equivalent I(3)Ba2Ca2 tetrahedra, edges with three equivalent I(2)Ba4Ca square pyramids, edges with two equivalent I(3)Ba2Ca2 tetrahedra,  a faceface with one I(2)Ba4Ca square pyramid, and  a faceface with one I(3)Ba2Ca2 tetrahedra. In the third I site, I(3) is bonded to two equivalent Ba(1) and two equivalent Ca(1) atoms to form distorted IBa2Ca2 tetrahedra that share corners with five equivalent I(2)Ba4Ca square pyramids, corners with four equivalent I(3)Ba2Ca2 tetrahedra, edges with two equivalent I(2)Ba4Ca square pyramids, edges with two equivalent I(3)Ba2Ca2 tetrahedra, and  a faceface with one I(2)Ba4Ca square pyramid.
Ba2CaI6 crystallizes in the monoclinic C2/c space group. Ba(1) is bonded in a 8-coordinate geometry to two equivalent I(1), two equivalent I(3), and four equivalent I(2) atoms. There is one shorter (3.43 Å) and one longer (3.56 Å) Ba(1)-I(1) bond length. There is one shorter (3.53 Å) and one longer (3.63 Å) Ba(1)-I(3) bond length. There are a spread of Ba(1)-I(2) bond distances ranging from 3.68-4.04 Å. Ca(1) is bonded in a 8-coordinate geometry to two equivalent I(1), two equivalent I(2), and four equivalent I(3) atoms. Both Ca(1)-I(1) bond lengths are 3.30 Å. Both Ca(1)-I(2) bond lengths are 3.40 Å. There are two shorter (3.28 Å) and two longer (3.41 Å) Ca(1)-I(3) bond lengths. There are three inequivalent I sites. In the first I site, I(1) is bonded in a distorted T-shaped geometry to two equivalent Ba(1) and one Ca(1) atom. In the second I site, I(2) is bonded to four equivalent Ba(1) and one Ca(1) atom to form distorted IBa4Ca square pyramids that share corners with four equivalent I(2)Ba4Ca square pyramids, corners with five equivalent I(3)Ba2Ca2 tetrahedra, edges with three equivalent I(2)Ba4Ca square pyramids, edges with two equivalent I(3)Ba2Ca2 tetrahedra,  a faceface with one I(2)Ba4Ca square pyramid, and  a faceface with one I(3)Ba2Ca2 tetrahedra. In the third I site, I(3) is bonded to two equivalent Ba(1) and two equivalent Ca(1) atoms to form distorted IBa2Ca2 tetrahedra that share corners with five equivalent I(2)Ba4Ca square pyramids, corners with four equivalent I(3)Ba2Ca2 tetrahedra, edges with two equivalent I(2)Ba4Ca square pyramids, edges with two equivalent I(3)Ba2Ca2 tetrahedra, and  a faceface with one I(2)Ba4Ca square pyramid.