La10Al5Br4 crystallizes in the tetragonal I4/mcm space group. There are three inequivalent La sites. In the first La site, La(1) is bonded in a 6-coordinate geometry to one Al(2), four equivalent Al(1), and one Br(2) atom. In the second La site, La(2) is bonded in a 8-coordinate geometry to three equivalent Al(1), two equivalent Br(2), and three equivalent Br(1) atoms. In the third La site, La(3) is bonded to two equivalent Al(2) and three equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing LaAl5 trigonal bipyramids. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 9-coordinate geometry to two equivalent La(1), three equivalent La(2), three equivalent La(3), and one Al(1) atom. In the second Al site, Al(2) is bonded in a distorted q6 geometry to two equivalent La(1) and eight equivalent La(3) atoms. There are two inequivalent Br sites. In the first Br site, Br(1) is bonded in a 6-coordinate geometry to six equivalent La(2) atoms. In the second Br site, Br(2) is bonded to one La(1) and four equivalent La(2) atoms to form corner-sharing BrLa5 square pyramids.
La10Al5Br4 crystallizes in the tetragonal I4/mcm space group. There are three inequivalent La sites. In the first La site, La(1) is bonded in a 6-coordinate geometry to one Al(2), four equivalent Al(1), and one Br(2) atom. The La(1)-Al(2) bond length is 3.26 Å. All La(1)-Al(1) bond lengths are 3.35 Å. The La(1)-Br(2) bond length is 3.22 Å. In the second La site, La(2) is bonded in a 8-coordinate geometry to three equivalent Al(1), two equivalent Br(2), and three equivalent Br(1) atoms. There is one shorter (3.23 Å) and two longer (3.24 Å) La(2)-Al(1) bond lengths. Both La(2)-Br(2) bond lengths are 3.11 Å. There is one shorter (3.23 Å) and two longer (3.54 Å) La(2)-Br(1) bond lengths. In the third La site, La(3) is bonded to two equivalent Al(2) and three equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing LaAl5 trigonal bipyramids. Both La(3)-Al(2) bond lengths are 3.45 Å. There are two shorter (3.33 Å) and one longer (3.38 Å) La(3)-Al(1) bond length. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 9-coordinate geometry to two equivalent La(1), three equivalent La(2), three equivalent La(3), and one Al(1) atom. The Al(1)-Al(1) bond length is 2.79 Å. In the second Al site, Al(2) is bonded in a distorted q6 geometry to two equivalent La(1) and eight equivalent La(3) atoms. There are two inequivalent Br sites. In the first Br site, Br(1) is bonded in a 6-coordinate geometry to six equivalent La(2) atoms. In the second Br site, Br(2) is bonded to one La(1) and four equivalent La(2) atoms to form corner-sharing BrLa5 square pyramids.