CsBa2Br5 crystallizes in the monoclinic P2_1/c space group. Cs(1) is bonded in a 9-coordinate geometry to two equivalent Br(1), two equivalent Br(2), two equivalent Br(4), and three equivalent Br(5) atoms. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to two equivalent Br(1), two equivalent Br(2), two equivalent Br(3), and two equivalent Br(4) atoms. In the second Ba site, Ba(2) is bonded to one Br(1), one Br(2), one Br(4), two equivalent Br(3), and two equivalent Br(5) atoms to form distorted edge-sharing BaBr7 pentagonal bipyramids. There are five inequivalent Br sites. In the first Br site, Br(1) is bonded to two equivalent Cs(1), one Ba(2), and two equivalent Ba(1) atoms to form distorted BrCs2Ba3 square pyramids that share corners with four equivalent Br(2)Cs2Ba3 square pyramids, corners with four equivalent Br(3)Ba4 tetrahedra,  an edgeedge with one Br(2)Cs2Ba3 square pyramid, edges with two equivalent Br(1)Cs2Ba3 square pyramids,  an edgeedge with one Br(3)Ba4 tetrahedra, and  a faceface with one Br(2)Cs2Ba3 square pyramid. In the second Br site, Br(2) is bonded to two equivalent Cs(1), one Ba(2), and two equivalent Ba(1) atoms to form BrCs2Ba3 square pyramids that share corners with four equivalent Br(1)Cs2Ba3 square pyramids, corners with four equivalent Br(2)Cs2Ba3 square pyramids, corners with two equivalent Br(3)Ba4 tetrahedra,  an edgeedge with one Br(1)Cs2Ba3 square pyramid, edges with two equivalent Br(3)Ba4 tetrahedra, and  a faceface with one Br(1)Cs2Ba3 square pyramid. In the third Br site, Br(3) is bonded to two equivalent Ba(1) and two equivalent Ba(2) atoms to form distorted BrBa4 tetrahedra that share corners with two equivalent Br(2)Cs2Ba3 square pyramids, corners with four equivalent Br(1)Cs2Ba3 square pyramids, corners with two equivalent Br(3)Ba4 tetrahedra,  an edgeedge with one Br(1)Cs2Ba3 square pyramid, edges with two equivalent Br(2)Cs2Ba3 square pyramids, and  an edgeedge with one Br(3)Ba4 tetrahedra. In the fourth Br site, Br(4) is bonded in a 5-coordinate geometry to two equivalent Cs(1), one Ba(2), and two equivalent Ba(1) atoms. In the fifth Br site, Br(5) is bonded in a 5-coordinate geometry to three equivalent Cs(1) and two equivalent Ba(2) atoms.
CsBa2Br5 crystallizes in the monoclinic P2_1/c space group. Cs(1) is bonded in a 9-coordinate geometry to two equivalent Br(1), two equivalent Br(2), two equivalent Br(4), and three equivalent Br(5) atoms. There is one shorter (3.71 Å) and one longer (3.82 Å) Cs(1)-Br(1) bond length. There is one shorter (3.69 Å) and one longer (3.79 Å) Cs(1)-Br(2) bond length. There is one shorter (3.71 Å) and one longer (4.13 Å) Cs(1)-Br(4) bond length. There are a spread of Cs(1)-Br(5) bond distances ranging from 3.58-4.16 Å. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to two equivalent Br(1), two equivalent Br(2), two equivalent Br(3), and two equivalent Br(4) atoms. There is one shorter (3.31 Å) and one longer (3.33 Å) Ba(1)-Br(1) bond length. There is one shorter (3.32 Å) and one longer (3.40 Å) Ba(1)-Br(2) bond length. There is one shorter (3.38 Å) and one longer (3.40 Å) Ba(1)-Br(3) bond length. There is one shorter (3.34 Å) and one longer (3.42 Å) Ba(1)-Br(4) bond length. In the second Ba site, Ba(2) is bonded to one Br(1), one Br(2), one Br(4), two equivalent Br(3), and two equivalent Br(5) atoms to form distorted edge-sharing BaBr7 pentagonal bipyramids. The Ba(2)-Br(1) bond length is 3.37 Å. The Ba(2)-Br(2) bond length is 3.35 Å. The Ba(2)-Br(4) bond length is 3.27 Å. Both Ba(2)-Br(3) bond lengths are 3.28 Å. There is one shorter (3.22 Å) and one longer (3.29 Å) Ba(2)-Br(5) bond length. There are five inequivalent Br sites. In the first Br site, Br(1) is bonded to two equivalent Cs(1), one Ba(2), and two equivalent Ba(1) atoms to form distorted BrCs2Ba3 square pyramids that share corners with four equivalent Br(2)Cs2Ba3 square pyramids, corners with four equivalent Br(3)Ba4 tetrahedra,  an edgeedge with one Br(2)Cs2Ba3 square pyramid, edges with two equivalent Br(1)Cs2Ba3 square pyramids,  an edgeedge with one Br(3)Ba4 tetrahedra, and  a faceface with one Br(2)Cs2Ba3 square pyramid. In the second Br site, Br(2) is bonded to two equivalent Cs(1), one Ba(2), and two equivalent Ba(1) atoms to form BrCs2Ba3 square pyramids that share corners with four equivalent Br(1)Cs2Ba3 square pyramids, corners with four equivalent Br(2)Cs2Ba3 square pyramids, corners with two equivalent Br(3)Ba4 tetrahedra,  an edgeedge with one Br(1)Cs2Ba3 square pyramid, edges with two equivalent Br(3)Ba4 tetrahedra, and  a faceface with one Br(1)Cs2Ba3 square pyramid. In the third Br site, Br(3) is bonded to two equivalent Ba(1) and two equivalent Ba(2) atoms to form distorted BrBa4 tetrahedra that share corners with two equivalent Br(2)Cs2Ba3 square pyramids, corners with four equivalent Br(1)Cs2Ba3 square pyramids, corners with two equivalent Br(3)Ba4 tetrahedra,  an edgeedge with one Br(1)Cs2Ba3 square pyramid, edges with two equivalent Br(2)Cs2Ba3 square pyramids, and  an edgeedge with one Br(3)Ba4 tetrahedra. In the fourth Br site, Br(4) is bonded in a 5-coordinate geometry to two equivalent Cs(1), one Ba(2), and two equivalent Ba(1) atoms. In the fifth Br site, Br(5) is bonded in a 5-coordinate geometry to three equivalent Cs(1) and two equivalent Ba(2) atoms.