BaYI5 crystallizes in the monoclinic C2/c space group. Ba(1) is bonded to one I(3), two equivalent I(1), and four equivalent I(2) atoms to form BaI7 pentagonal bipyramids that share corners with four equivalent Y(1)I6 octahedra, edges with two equivalent Y(1)I6 octahedra, and edges with two equivalent Ba(1)I7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 3-37°. Y(1) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(3) atoms to form YI6 octahedra that share corners with two equivalent Y(1)I6 octahedra, corners with four equivalent Ba(1)I7 pentagonal bipyramids, and edges with two equivalent Ba(1)I7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 30°. There are three inequivalent I sites. In the first I site, I(1) is bonded in a linear geometry to one Ba(1) and one Y(1) atom. In the second I site, I(2) is bonded in a distorted trigonal planar geometry to two equivalent Ba(1) and one Y(1) atom. In the third I site, I(3) is bonded in a 3-coordinate geometry to one Ba(1) and two equivalent Y(1) atoms.
BaYI5 crystallizes in the monoclinic C2/c space group. Ba(1) is bonded to one I(3), two equivalent I(1), and four equivalent I(2) atoms to form BaI7 pentagonal bipyramids that share corners with four equivalent Y(1)I6 octahedra, edges with two equivalent Y(1)I6 octahedra, and edges with two equivalent Ba(1)I7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 3-37°. The Ba(1)-I(3) bond length is 3.60 Å. Both Ba(1)-I(1) bond lengths are 3.42 Å. There are two shorter (3.60 Å) and two longer (3.68 Å) Ba(1)-I(2) bond lengths. Y(1) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(3) atoms to form YI6 octahedra that share corners with two equivalent Y(1)I6 octahedra, corners with four equivalent Ba(1)I7 pentagonal bipyramids, and edges with two equivalent Ba(1)I7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 30°. Both Y(1)-I(1) bond lengths are 2.98 Å. Both Y(1)-I(2) bond lengths are 3.05 Å. Both Y(1)-I(3) bond lengths are 3.08 Å. There are three inequivalent I sites. In the first I site, I(1) is bonded in a linear geometry to one Ba(1) and one Y(1) atom. In the second I site, I(2) is bonded in a distorted trigonal planar geometry to two equivalent Ba(1) and one Y(1) atom. In the third I site, I(3) is bonded in a 3-coordinate geometry to one Ba(1) and two equivalent Y(1) atoms.