KEu2I5 crystallizes in the monoclinic P2_1/c space group. K(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(5) atoms. There are two inequivalent Eu sites. In the first Eu site, Eu(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. In the second Eu site, Eu(2) is bonded to one I(1), one I(2), one I(3), two equivalent I(4), and two equivalent I(5) atoms to form distorted edge-sharing EuI7 pentagonal bipyramids. There are five inequivalent I sites. In the first I site, I(1) is bonded to two equivalent K(1), one Eu(2), and two equivalent Eu(1) atoms to form IK2Eu3 trigonal bipyramids that share corners with four equivalent I(3)K2Eu3 square pyramids, corners with four equivalent I(1)K2Eu3 trigonal bipyramids, corners with two equivalent I(4)Eu4 trigonal pyramids, corners with two equivalent I(5)K2Eu2 trigonal pyramids,  an edgeedge with one I(3)K2Eu3 square pyramid, edges with two equivalent I(4)Eu4 trigonal pyramids, edges with two equivalent I(5)K2Eu2 trigonal pyramids, and  a faceface with one I(3)K2Eu3 square pyramid. In the second I site, I(2) is bonded in a 5-coordinate geometry to two equivalent K(1), one Eu(2), and two equivalent Eu(1) atoms. In the third I site, I(3) is bonded to two equivalent K(1), one Eu(2), and two equivalent Eu(1) atoms to form IK2Eu3 square pyramids that share corners with four equivalent I(1)K2Eu3 trigonal bipyramids, corners with four equivalent I(4)Eu4 trigonal pyramids, corners with four equivalent I(5)K2Eu2 trigonal pyramids, edges with two equivalent I(3)K2Eu3 square pyramids,  an edgeedge with one I(1)K2Eu3 trigonal bipyramid,  an edgeedge with one I(4)Eu4 trigonal pyramid,  an edgeedge with one I(5)K2Eu2 trigonal pyramid, and  a faceface with one I(1)K2Eu3 trigonal bipyramid. In the fourth I site, I(4) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form distorted IEu4 trigonal pyramids that share corners with four equivalent I(3)K2Eu3 square pyramids, corners with two equivalent I(1)K2Eu3 trigonal bipyramids, corners with two equivalent I(4)Eu4 trigonal pyramids, corners with four equivalent I(5)K2Eu2 trigonal pyramids,  an edgeedge with one I(3)K2Eu3 square pyramid, edges with two equivalent I(1)K2Eu3 trigonal bipyramids, and  an edgeedge with one I(4)Eu4 trigonal pyramid. In the fifth I site, I(5) is bonded to two equivalent K(1) and two equivalent Eu(2) atoms to form distorted IK2Eu2 trigonal pyramids that share corners with four equivalent I(3)K2Eu3 square pyramids, corners with two equivalent I(1)K2Eu3 trigonal bipyramids, corners with two equivalent I(5)K2Eu2 trigonal pyramids, corners with four equivalent I(4)Eu4 trigonal pyramids,  an edgeedge with one I(3)K2Eu3 square pyramid, edges with two equivalent I(1)K2Eu3 trigonal bipyramids, and  an edgeedge with one I(5)K2Eu2 trigonal pyramid.
KEu2I5 crystallizes in the monoclinic P2_1/c space group. K(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(5) atoms. There is one shorter (3.67 Å) and one longer (3.72 Å) K(1)-I(1) bond length. There is one shorter (3.74 Å) and one longer (4.03 Å) K(1)-I(2) bond length. There is one shorter (3.73 Å) and one longer (3.79 Å) K(1)-I(3) bond length. There is one shorter (3.58 Å) and one longer (3.67 Å) K(1)-I(5) bond length. There are two inequivalent Eu sites. In the first Eu site, Eu(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 (3.38 Å) and one longer (3.48 Å) Eu(1)-I(1) bond length. There is one shorter (3.40 Å) and one longer (3.56 Å) Eu(1)-I(2) bond length. There is one shorter (3.39 Å) and one longer (3.43 Å) Eu(1)-I(3) bond length. There is one shorter (3.43 Å) and one longer (3.47 Å) Eu(1)-I(4) bond length. In the second Eu site, Eu(2) is bonded to one I(1), one I(2), one I(3), two equivalent I(4), and two equivalent I(5) atoms to form distorted edge-sharing EuI7 pentagonal bipyramids. The Eu(2)-I(1) bond length is 3.35 Å. The Eu(2)-I(2) bond length is 3.34 Å. The Eu(2)-I(3) bond length is 3.45 Å. There is one shorter (3.29 Å) and one longer (3.32 Å) Eu(2)-I(4) bond length. There is one shorter (3.23 Å) and one longer (3.35 Å) Eu(2)-I(5) bond length. There are five inequivalent I sites. In the first I site, I(1) is bonded to two equivalent K(1), one Eu(2), and two equivalent Eu(1) atoms to form IK2Eu3 trigonal bipyramids that share corners with four equivalent I(3)K2Eu3 square pyramids, corners with four equivalent I(1)K2Eu3 trigonal bipyramids, corners with two equivalent I(4)Eu4 trigonal pyramids, corners with two equivalent I(5)K2Eu2 trigonal pyramids,  an edgeedge with one I(3)K2Eu3 square pyramid, edges with two equivalent I(4)Eu4 trigonal pyramids, edges with two equivalent I(5)K2Eu2 trigonal pyramids, and  a faceface with one I(3)K2Eu3 square pyramid. In the second I site, I(2) is bonded in a 5-coordinate geometry to two equivalent K(1), one Eu(2), and two equivalent Eu(1) atoms. In the third I site, I(3) is bonded to two equivalent K(1), one Eu(2), and two equivalent Eu(1) atoms to form IK2Eu3 square pyramids that share corners with four equivalent I(1)K2Eu3 trigonal bipyramids, corners with four equivalent I(4)Eu4 trigonal pyramids, corners with four equivalent I(5)K2Eu2 trigonal pyramids, edges with two equivalent I(3)K2Eu3 square pyramids,  an edgeedge with one I(1)K2Eu3 trigonal bipyramid,  an edgeedge with one I(4)Eu4 trigonal pyramid,  an edgeedge with one I(5)K2Eu2 trigonal pyramid, and  a faceface with one I(1)K2Eu3 trigonal bipyramid. In the fourth I site, I(4) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form distorted IEu4 trigonal pyramids that share corners with four equivalent I(3)K2Eu3 square pyramids, corners with two equivalent I(1)K2Eu3 trigonal bipyramids, corners with two equivalent I(4)Eu4 trigonal pyramids, corners with four equivalent I(5)K2Eu2 trigonal pyramids,  an edgeedge with one I(3)K2Eu3 square pyramid, edges with two equivalent I(1)K2Eu3 trigonal bipyramids, and  an edgeedge with one I(4)Eu4 trigonal pyramid. In the fifth I site, I(5) is bonded to two equivalent K(1) and two equivalent Eu(2) atoms to form distorted IK2Eu2 trigonal pyramids that share corners with four equivalent I(3)K2Eu3 square pyramids, corners with two equivalent I(1)K2Eu3 trigonal bipyramids, corners with two equivalent I(5)K2Eu2 trigonal pyramids, corners with four equivalent I(4)Eu4 trigonal pyramids,  an edgeedge with one I(3)K2Eu3 square pyramid, edges with two equivalent I(1)K2Eu3 trigonal bipyramids, and  an edgeedge with one I(5)K2Eu2 trigonal pyramid.