BaLaI5 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 La(1)I6 octahedra, edges with two equivalent La(1)I6 octahedra, and edges with two equivalent Ba(1)I7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 2-39°. La(1) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(3) atoms to form LaI6 octahedra that share corners with two equivalent La(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 36°. 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 La(1) atom. In the second I site, I(2) is bonded in a distorted trigonal planar geometry to two equivalent Ba(1) and one La(1) atom. In the third I site, I(3) is bonded in a distorted trigonal planar geometry to one Ba(1) and two equivalent La(1) atoms.
BaLaI5 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 La(1)I6 octahedra, edges with two equivalent La(1)I6 octahedra, and edges with two equivalent Ba(1)I7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 2-39°. The Ba(1)-I(3) bond length is 3.61 Å. Both Ba(1)-I(1) bond lengths are 3.41 Å. There are two shorter (3.58 Å) and two longer (3.80 Å) Ba(1)-I(2) bond lengths. La(1) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(3) atoms to form LaI6 octahedra that share corners with two equivalent La(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 36°. Both La(1)-I(1) bond lengths are 3.10 Å. Both La(1)-I(2) bond lengths are 3.18 Å. Both La(1)-I(3) bond lengths are 3.20 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 La(1) atom. In the second I site, I(2) is bonded in a distorted trigonal planar geometry to two equivalent Ba(1) and one La(1) atom. In the third I site, I(3) is bonded in a distorted trigonal planar geometry to one Ba(1) and two equivalent La(1) atoms.