RbBa2I5 crystallizes in the monoclinic P2_1/c space group. Rb(1) is bonded in a 8-coordinate geometry to two equivalent I(1), two equivalent I(2), two equivalent I(3), and two equivalent I(4) atoms. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to two equivalent I(2), two equivalent I(3), two equivalent I(4), and two equivalent I(5) atoms. In the second Ba site, Ba(2) is bonded to one I(2), one I(3), one I(4), two equivalent I(1), and two equivalent I(5) atoms to form distorted edge-sharing BaI7 pentagonal bipyramids. There are five inequivalent I sites. In the first I site, I(1) is bonded to two equivalent Rb(1) and two equivalent Ba(2) atoms to form distorted IRb2Ba2 trigonal pyramids that share corners with two equivalent I(3)Rb2Ba3 square pyramids, corners with four equivalent I(4)Rb2Ba3 square pyramids, corners with two equivalent I(1)Rb2Ba2 trigonal pyramids, corners with four equivalent I(5)Ba4 trigonal pyramids,  an edgeedge with one I(4)Rb2Ba3 square pyramid, edges with two equivalent I(3)Rb2Ba3 square pyramids, and  an edgeedge with one I(1)Rb2Ba2 trigonal pyramid. In the second I site, I(2) is bonded in a 5-coordinate geometry to two equivalent Rb(1), one Ba(2), and two equivalent Ba(1) atoms. In the third I site, I(3) is bonded to two equivalent Rb(1), one Ba(2), and two equivalent Ba(1) atoms to form IRb2Ba3 square pyramids that share corners with four equivalent I(3)Rb2Ba3 square pyramids, corners with four equivalent I(4)Rb2Ba3 square pyramids, corners with two equivalent I(5)Ba4 trigonal pyramids, corners with two equivalent I(1)Rb2Ba2 trigonal pyramids,  an edgeedge with one I(4)Rb2Ba3 square pyramid, edges with two equivalent I(5)Ba4 trigonal pyramids, edges with two equivalent I(1)Rb2Ba2 trigonal pyramids, and  a faceface with one I(4)Rb2Ba3 square pyramid. In the fourth I site, I(4) is bonded to two equivalent Rb(1), one Ba(2), and two equivalent Ba(1) atoms to form IRb2Ba3 square pyramids that share corners with four equivalent I(3)Rb2Ba3 square pyramids, corners with four equivalent I(5)Ba4 trigonal pyramids, corners with four equivalent I(1)Rb2Ba2 trigonal pyramids,  an edgeedge with one I(3)Rb2Ba3 square pyramid, edges with two equivalent I(4)Rb2Ba3 square pyramids,  an edgeedge with one I(5)Ba4 trigonal pyramid,  an edgeedge with one I(1)Rb2Ba2 trigonal pyramid, and  a faceface with one I(3)Rb2Ba3 square pyramid. In the fifth I site, I(5) is bonded to two equivalent Ba(1) and two equivalent Ba(2) atoms to form distorted IBa4 trigonal pyramids that share corners with two equivalent I(3)Rb2Ba3 square pyramids, corners with four equivalent I(4)Rb2Ba3 square pyramids, corners with two equivalent I(5)Ba4 trigonal pyramids, corners with four equivalent I(1)Rb2Ba2 trigonal pyramids,  an edgeedge with one I(4)Rb2Ba3 square pyramid, edges with two equivalent I(3)Rb2Ba3 square pyramids, and  an edgeedge with one I(5)Ba4 trigonal pyramid.
RbBa2I5 crystallizes in the monoclinic P2_1/c space group. Rb(1) is bonded in a 8-coordinate geometry to two equivalent I(1), two equivalent I(2), two equivalent I(3), and two equivalent I(4) atoms. There is one shorter (3.69 Å) and one longer (3.74 Å) Rb(1)-I(1) bond length. There is one shorter (3.96 Å) and one longer (4.18 Å) Rb(1)-I(2) bond length. Both Rb(1)-I(3) bond lengths are 3.86 Å. There is one shorter (3.87 Å) and one longer (3.93 Å) Rb(1)-I(4) bond length. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to two equivalent I(2), two equivalent I(3), two equivalent I(4), and two equivalent I(5) atoms. There is one shorter (3.60 Å) and one longer (3.68 Å) Ba(1)-I(2) bond length. There is one shorter (3.58 Å) and one longer (3.63 Å) Ba(1)-I(3) bond length. There is one shorter (3.59 Å) and one longer (3.61 Å) Ba(1)-I(4) bond length. Both Ba(1)-I(5) bond lengths are 3.62 Å. In the second Ba site, Ba(2) is bonded to one I(2), one I(3), one I(4), two equivalent I(1), and two equivalent I(5) atoms to form distorted edge-sharing BaI7 pentagonal bipyramids. The Ba(2)-I(2) bond length is 3.52 Å. The Ba(2)-I(3) bond length is 3.58 Å. The Ba(2)-I(4) bond length is 3.61 Å. There is one shorter (3.42 Å) and one longer (3.51 Å) Ba(2)-I(1) bond length. There is one shorter (3.48 Å) and one longer (3.52 Å) Ba(2)-I(5) bond length. There are five inequivalent I sites. In the first I site, I(1) is bonded to two equivalent Rb(1) and two equivalent Ba(2) atoms to form distorted IRb2Ba2 trigonal pyramids that share corners with two equivalent I(3)Rb2Ba3 square pyramids, corners with four equivalent I(4)Rb2Ba3 square pyramids, corners with two equivalent I(1)Rb2Ba2 trigonal pyramids, corners with four equivalent I(5)Ba4 trigonal pyramids,  an edgeedge with one I(4)Rb2Ba3 square pyramid, edges with two equivalent I(3)Rb2Ba3 square pyramids, and  an edgeedge with one I(1)Rb2Ba2 trigonal pyramid. In the second I site, I(2) is bonded in a 5-coordinate geometry to two equivalent Rb(1), one Ba(2), and two equivalent Ba(1) atoms. In the third I site, I(3) is bonded to two equivalent Rb(1), one Ba(2), and two equivalent Ba(1) atoms to form IRb2Ba3 square pyramids that share corners with four equivalent I(3)Rb2Ba3 square pyramids, corners with four equivalent I(4)Rb2Ba3 square pyramids, corners with two equivalent I(5)Ba4 trigonal pyramids, corners with two equivalent I(1)Rb2Ba2 trigonal pyramids,  an edgeedge with one I(4)Rb2Ba3 square pyramid, edges with two equivalent I(5)Ba4 trigonal pyramids, edges with two equivalent I(1)Rb2Ba2 trigonal pyramids, and  a faceface with one I(4)Rb2Ba3 square pyramid. In the fourth I site, I(4) is bonded to two equivalent Rb(1), one Ba(2), and two equivalent Ba(1) atoms to form IRb2Ba3 square pyramids that share corners with four equivalent I(3)Rb2Ba3 square pyramids, corners with four equivalent I(5)Ba4 trigonal pyramids, corners with four equivalent I(1)Rb2Ba2 trigonal pyramids,  an edgeedge with one I(3)Rb2Ba3 square pyramid, edges with two equivalent I(4)Rb2Ba3 square pyramids,  an edgeedge with one I(5)Ba4 trigonal pyramid,  an edgeedge with one I(1)Rb2Ba2 trigonal pyramid, and  a faceface with one I(3)Rb2Ba3 square pyramid. In the fifth I site, I(5) is bonded to two equivalent Ba(1) and two equivalent Ba(2) atoms to form distorted IBa4 trigonal pyramids that share corners with two equivalent I(3)Rb2Ba3 square pyramids, corners with four equivalent I(4)Rb2Ba3 square pyramids, corners with two equivalent I(5)Ba4 trigonal pyramids, corners with four equivalent I(1)Rb2Ba2 trigonal pyramids,  an edgeedge with one I(4)Rb2Ba3 square pyramid, edges with two equivalent I(3)Rb2Ba3 square pyramids, and  an edgeedge with one I(5)Ba4 trigonal pyramid.