Ba2YI7 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one I(1), two equivalent I(2), two equivalent I(3), and two equivalent I(4) atoms to form distorted BaI7 pentagonal bipyramids that share corners with two equivalent Y(1)I6 pentagonal pyramids, edges with two equivalent Ba(2)I7 pentagonal bipyramids, edges with two equivalent Y(1)I6 pentagonal pyramids, and  a faceface with one Ba(2)I7 pentagonal bipyramid. In the second Ba site, Ba(2) is bonded to one I(1), two equivalent I(2), two equivalent I(3), and two equivalent I(4) atoms to form distorted BaI7 pentagonal bipyramids that share corners with two equivalent Y(1)I6 pentagonal pyramids, edges with two equivalent Ba(1)I7 pentagonal bipyramids, edges with two equivalent Y(1)I6 pentagonal pyramids, and  a faceface with one Ba(1)I7 pentagonal bipyramid. Y(1) is bonded to two equivalent I(2), two equivalent I(3), and two equivalent I(4) atoms to form distorted YI6 pentagonal pyramids that share corners with two equivalent Ba(1)I7 pentagonal bipyramids, corners with two equivalent Ba(2)I7 pentagonal bipyramids, edges with two equivalent Ba(1)I7 pentagonal bipyramids, and edges with two equivalent Ba(2)I7 pentagonal bipyramids. There are four inequivalent I sites. In the first I site, I(1) is bonded in an L-shaped geometry to one Ba(1) and one Ba(2) atom. In the second I site, I(2) is bonded in a distorted trigonal non-coplanar geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the third I site, I(3) is bonded in a trigonal non-coplanar geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the fourth I site, I(4) is bonded in a distorted T-shaped geometry to one Ba(1), one Ba(2), and one Y(1) atom.
Ba2YI7 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one I(1), two equivalent I(2), two equivalent I(3), and two equivalent I(4) atoms to form distorted BaI7 pentagonal bipyramids that share corners with two equivalent Y(1)I6 pentagonal pyramids, edges with two equivalent Ba(2)I7 pentagonal bipyramids, edges with two equivalent Y(1)I6 pentagonal pyramids, and  a faceface with one Ba(2)I7 pentagonal bipyramid. The Ba(1)-I(1) bond length is 3.35 Å. Both Ba(1)-I(2) bond lengths are 3.56 Å. Both Ba(1)-I(3) bond lengths are 3.53 Å. Both Ba(1)-I(4) bond lengths are 3.60 Å. In the second Ba site, Ba(2) is bonded to one I(1), two equivalent I(2), two equivalent I(3), and two equivalent I(4) atoms to form distorted BaI7 pentagonal bipyramids that share corners with two equivalent Y(1)I6 pentagonal pyramids, edges with two equivalent Ba(1)I7 pentagonal bipyramids, edges with two equivalent Y(1)I6 pentagonal pyramids, and  a faceface with one Ba(1)I7 pentagonal bipyramid. The Ba(2)-I(1) bond length is 3.32 Å. Both Ba(2)-I(2) bond lengths are 3.64 Å. Both Ba(2)-I(3) bond lengths are 3.58 Å. Both Ba(2)-I(4) bond lengths are 3.56 Å. Y(1) is bonded to two equivalent I(2), two equivalent I(3), and two equivalent I(4) atoms to form distorted YI6 pentagonal pyramids that share corners with two equivalent Ba(1)I7 pentagonal bipyramids, corners with two equivalent Ba(2)I7 pentagonal bipyramids, edges with two equivalent Ba(1)I7 pentagonal bipyramids, and edges with two equivalent Ba(2)I7 pentagonal bipyramids. Both Y(1)-I(2) bond lengths are 3.12 Å. Both Y(1)-I(3) bond lengths are 3.09 Å. Both Y(1)-I(4) bond lengths are 3.05 Å. There are four inequivalent I sites. In the first I site, I(1) is bonded in an L-shaped geometry to one Ba(1) and one Ba(2) atom. In the second I site, I(2) is bonded in a distorted trigonal non-coplanar geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the third I site, I(3) is bonded in a trigonal non-coplanar geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the fourth I site, I(4) is bonded in a distorted T-shaped geometry to one Ba(1), one Ba(2), and one Y(1) atom.