La4B2CI5 crystallizes in the monoclinic C2/m space group. There are four inequivalent La sites. In the first La site, La(1) is bonded to two equivalent B(1), two equivalent B(2), one I(2), one I(5), and two equivalent I(1) atoms to form distorted LaB4I4 hexagonal bipyramids that share  a cornercorner with one La(3)CI5 octahedra and edges with three equivalent La(1)B4I4 hexagonal bipyramids. The corner-sharing octahedra are not tilted. In the second La site, La(2) is bonded in a 9-coordinate geometry to two equivalent B(1), two equivalent B(2), one I(4), two equivalent I(2), and two equivalent I(5) atoms. In the third La site, La(3) is bonded to one C(1), one I(2), two equivalent I(3), and two equivalent I(4) atoms to form distorted LaCI5 octahedra that share  a cornercorner with one La(1)B4I4 hexagonal bipyramid and edges with two equivalent La(3)CI5 octahedra. In the fourth La site, La(4) is bonded in a 8-coordinate geometry to four equivalent C(1), one I(3), one I(4), and two equivalent I(1) atoms. There are two inequivalent B sites. In the first B site, B(1) is bonded in a 7-coordinate geometry to two equivalent La(1), two equivalent La(2), one B(1), and two equivalent B(2) atoms. In the second B site, B(2) is bonded in a 7-coordinate geometry to two equivalent La(1), two equivalent La(2), one B(2), and two equivalent B(1) atoms. C(1) is bonded in a 6-coordinate geometry to one La(3), four equivalent La(4), and one C(1) atom. There are five inequivalent I sites. In the first I site, I(4) is bonded in a distorted see-saw-like geometry to one La(2), one La(4), and two equivalent La(3) atoms. In the second I site, I(5) is bonded in a distorted T-shaped geometry to one La(1) and two equivalent La(2) atoms. In the third I site, I(1) is bonded in a square co-planar geometry to two equivalent La(1) and two equivalent La(4) atoms. In the fourth I site, I(2) is bonded in a distorted see-saw-like geometry to one La(1), one La(3), and two equivalent La(2) atoms. In the fifth I site, I(3) is bonded in a distorted T-shaped geometry to one La(4) and two equivalent La(3) atoms.
La4B2CI5 crystallizes in the monoclinic C2/m space group. There are four inequivalent La sites. In the first La site, La(1) is bonded to two equivalent B(1), two equivalent B(2), one I(2), one I(5), and two equivalent I(1) atoms to form distorted LaB4I4 hexagonal bipyramids that share  a cornercorner with one La(3)CI5 octahedra and edges with three equivalent La(1)B4I4 hexagonal bipyramids. The corner-sharing octahedra are not tilted. Both La(1)-B(1) bond lengths are 2.67 Å. Both La(1)-B(2) bond lengths are 2.66 Å. The La(1)-I(2) bond length is 3.35 Å. The La(1)-I(5) bond length is 3.29 Å. Both La(1)-I(1) bond lengths are 3.46 Å. In the second La site, La(2) is bonded in a 9-coordinate geometry to two equivalent B(1), two equivalent B(2), one I(4), two equivalent I(2), and two equivalent I(5) atoms. Both La(2)-B(1) bond lengths are 2.67 Å. Both La(2)-B(2) bond lengths are 2.84 Å. The La(2)-I(4) bond length is 3.76 Å. Both La(2)-I(2) bond lengths are 3.34 Å. Both La(2)-I(5) bond lengths are 3.29 Å. In the third La site, La(3) is bonded to one C(1), one I(2), two equivalent I(3), and two equivalent I(4) atoms to form distorted LaCI5 octahedra that share  a cornercorner with one La(1)B4I4 hexagonal bipyramid and edges with two equivalent La(3)CI5 octahedra. The La(3)-C(1) bond length is 2.32 Å. The La(3)-I(2) bond length is 3.54 Å. Both La(3)-I(3) bond lengths are 3.23 Å. Both La(3)-I(4) bond lengths are 3.29 Å. In the fourth La site, La(4) is bonded in a 8-coordinate geometry to four equivalent C(1), one I(3), one I(4), and two equivalent I(1) atoms. There are two shorter (2.82 Å) and two longer (2.83 Å) La(4)-C(1) bond lengths. The La(4)-I(3) bond length is 3.35 Å. The La(4)-I(4) bond length is 3.37 Å. Both La(4)-I(1) bond lengths are 3.44 Å. There are two inequivalent B sites. In the first B site, B(1) is bonded in a 7-coordinate geometry to two equivalent La(1), two equivalent La(2), one B(1), and two equivalent B(2) atoms. The B(1)-B(1) bond length is 1.91 Å. Both B(1)-B(2) bond lengths are 1.66 Å. In the second B site, B(2) is bonded in a 7-coordinate geometry to two equivalent La(1), two equivalent La(2), one B(2), and two equivalent B(1) atoms. The B(2)-B(2) bond length is 1.59 Å. C(1) is bonded in a 6-coordinate geometry to one La(3), four equivalent La(4), and one C(1) atom. The C(1)-C(1) bond length is 1.37 Å. There are five inequivalent I sites. In the first I site, I(4) is bonded in a distorted see-saw-like geometry to one La(2), one La(4), and two equivalent La(3) atoms. In the second I site, I(5) is bonded in a distorted T-shaped geometry to one La(1) and two equivalent La(2) atoms. In the third I site, I(1) is bonded in a square co-planar geometry to two equivalent La(1) and two equivalent La(4) atoms. In the fourth I site, I(2) is bonded in a distorted see-saw-like geometry to one La(1), one La(3), and two equivalent La(2) atoms. In the fifth I site, I(3) is bonded in a distorted T-shaped geometry to one La(4) and two equivalent La(3) atoms.