BaCa2I6 is zeta iron carbide-derived structured and crystallizes in the monoclinic Pc space group. Ba(1) is bonded in a 6-coordinate geometry to one I(1), one I(2), one I(3), one I(4), one I(5), and one I(6) atom. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one I(1), one I(2), one I(3), one I(4), one I(5), and one I(6) atom to form corner-sharing CaI6 octahedra. The corner-sharing octahedral tilt angles range from 36-42°. In the second Ca site, Ca(2) is bonded to one I(1), one I(2), one I(3), one I(4), one I(5), and one I(6) atom to form corner-sharing CaI6 octahedra. The corner-sharing octahedral tilt angles range from 36-42°. There are six inequivalent I sites. In the first I site, I(1) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(1), and one Ca(2) atom. In the second I site, I(2) is bonded in a distorted T-shaped geometry to one Ba(1), one Ca(1), and one Ca(2) atom. In the third I site, I(3) is bonded in a T-shaped geometry to one Ba(1), one Ca(1), and one Ca(2) atom. In the fourth I site, I(4) is bonded in a distorted trigonal non-coplanar geometry to one Ba(1), one Ca(1), and one Ca(2) atom. In the fifth I site, I(5) is bonded in a distorted trigonal planar geometry to one Ba(1), one Ca(1), and one Ca(2) atom. In the sixth I site, I(6) is bonded in a distorted trigonal planar geometry to one Ba(1), one Ca(1), and one Ca(2) atom.
BaCa2I6 is zeta iron carbide-derived structured and crystallizes in the monoclinic Pc space group. Ba(1) is bonded in a 6-coordinate geometry to one I(1), one I(2), one I(3), one I(4), one I(5), and one I(6) atom. The Ba(1)-I(1) bond length is 3.70 Å. The Ba(1)-I(2) bond length is 3.47 Å. The Ba(1)-I(3) bond length is 3.53 Å. The Ba(1)-I(4) bond length is 3.46 Å. The Ba(1)-I(5) bond length is 3.48 Å. The Ba(1)-I(6) bond length is 3.48 Å. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one I(1), one I(2), one I(3), one I(4), one I(5), and one I(6) atom to form corner-sharing CaI6 octahedra. The corner-sharing octahedral tilt angles range from 36-42°. The Ca(1)-I(1) bond length is 3.18 Å. The Ca(1)-I(2) bond length is 3.14 Å. The Ca(1)-I(3) bond length is 3.15 Å. The Ca(1)-I(4) bond length is 3.14 Å. The Ca(1)-I(5) bond length is 3.13 Å. The Ca(1)-I(6) bond length is 3.13 Å. In the second Ca site, Ca(2) is bonded to one I(1), one I(2), one I(3), one I(4), one I(5), and one I(6) atom to form corner-sharing CaI6 octahedra. The corner-sharing octahedral tilt angles range from 36-42°. The Ca(2)-I(1) bond length is 3.16 Å. The Ca(2)-I(2) bond length is 3.13 Å. The Ca(2)-I(3) bond length is 3.17 Å. The Ca(2)-I(4) bond length is 3.16 Å. The Ca(2)-I(5) bond length is 3.13 Å. The Ca(2)-I(6) bond length is 3.16 Å. There are six inequivalent I sites. In the first I site, I(1) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(1), and one Ca(2) atom. In the second I site, I(2) is bonded in a distorted T-shaped geometry to one Ba(1), one Ca(1), and one Ca(2) atom. In the third I site, I(3) is bonded in a T-shaped geometry to one Ba(1), one Ca(1), and one Ca(2) atom. In the fourth I site, I(4) is bonded in a distorted trigonal non-coplanar geometry to one Ba(1), one Ca(1), and one Ca(2) atom. In the fifth I site, I(5) is bonded in a distorted trigonal planar geometry to one Ba(1), one Ca(1), and one Ca(2) atom. In the sixth I site, I(6) is bonded in a distorted trigonal planar geometry to one Ba(1), one Ca(1), and one Ca(2) atom.