La5C2I9 crystallizes in the triclinic P-1 space group. There are five inequivalent La sites. In the first La site, La(1) is bonded in a 9-coordinate geometry to one C(1), one C(2), one I(2), one I(3), one I(4), one I(5), one I(6), one I(8), and one I(9) atom. In the second La site, La(2) is bonded in a 7-coordinate geometry to one C(2), one I(1), one I(5), one I(6), one I(8), and two equivalent I(3) atoms. In the third La site, La(3) is bonded to one C(1), one C(2), one I(4), one I(7), two equivalent I(6), and two equivalent I(9) atoms to form distorted edge-sharing LaC2I6 hexagonal bipyramids. In the fourth La site, La(4) is bonded in a distorted single-bond geometry to one C(1), one I(1), one I(2), one I(4), one I(8), one I(9), and two equivalent I(7) atoms. In the fifth La site, La(5) is bonded in a 8-coordinate geometry to one C(1), one C(2), one I(1), one I(3), one I(4), one I(5), and two equivalent I(2) atoms. There are two inequivalent C sites. In the first C site, C(1) is bonded in a 5-coordinate geometry to one La(1), one La(3), one La(4), one La(5), and one C(2) atom. In the second C site, C(2) is bonded in a 5-coordinate geometry to one La(1), one La(2), one La(3), one La(5), and one C(1) atom. There are nine inequivalent I sites. In the first I site, I(1) is bonded in a distorted trigonal non-coplanar geometry to one La(2), one La(4), and one La(5) atom. In the second I site, I(2) is bonded in a 4-coordinate geometry to one La(1), one La(4), and two equivalent La(5) atoms. In the third I site, I(3) is bonded in a 4-coordinate geometry to one La(1), one La(5), and two equivalent La(2) atoms. In the fourth I site, I(4) is bonded to one La(1), one La(3), one La(4), and one La(5) atom to form a mixture of distorted edge and corner-sharing ILa4 tetrahedra. In the fifth I site, I(5) is bonded in a distorted trigonal non-coplanar geometry to one La(1), one La(2), and one La(5) atom. In the sixth I site, I(6) is bonded to one La(1), one La(2), and two equivalent La(3) atoms to form a mixture of distorted edge and corner-sharing ILa4 tetrahedra. In the seventh I site, I(7) is bonded in a 3-coordinate geometry to one La(3) and two equivalent La(4) atoms. In the eighth I site, I(8) is bonded in a 3-coordinate geometry to one La(1), one La(2), and one La(4) atom. In the ninth I site, I(9) is bonded in a 4-coordinate geometry to one La(1), one La(4), and two equivalent La(3) atoms.
La5C2I9 crystallizes in the triclinic P-1 space group. There are five inequivalent La sites. In the first La site, La(1) is bonded in a 9-coordinate geometry to one C(1), one C(2), one I(2), one I(3), one I(4), one I(5), one I(6), one I(8), and one I(9) atom. The La(1)-C(1) bond length is 2.54 Å. The La(1)-C(2) bond length is 2.53 Å. The La(1)-I(2) bond length is 3.92 Å. The La(1)-I(3) bond length is 3.39 Å. The La(1)-I(4) bond length is 3.36 Å. The La(1)-I(5) bond length is 3.41 Å. The La(1)-I(6) bond length is 3.45 Å. The La(1)-I(8) bond length is 3.32 Å. The La(1)-I(9) bond length is 3.80 Å. In the second La site, La(2) is bonded in a 7-coordinate geometry to one C(2), one I(1), one I(5), one I(6), one I(8), and two equivalent I(3) atoms. The La(2)-C(2) bond length is 2.37 Å. The La(2)-I(1) bond length is 3.45 Å. The La(2)-I(5) bond length is 3.26 Å. The La(2)-I(6) bond length is 3.35 Å. The La(2)-I(8) bond length is 3.20 Å. There is one shorter (3.35 Å) and one longer (3.63 Å) La(2)-I(3) bond length. In the third La site, La(3) is bonded to one C(1), one C(2), one I(4), one I(7), two equivalent I(6), and two equivalent I(9) atoms to form distorted edge-sharing LaC2I6 hexagonal bipyramids. The La(3)-C(1) bond length is 2.51 Å. The La(3)-C(2) bond length is 2.46 Å. The La(3)-I(4) bond length is 3.47 Å. The La(3)-I(7) bond length is 3.30 Å. There is one shorter (3.43 Å) and one longer (3.57 Å) La(3)-I(6) bond length. There is one shorter (3.30 Å) and one longer (3.38 Å) La(3)-I(9) bond length. In the fourth La site, La(4) is bonded in a distorted single-bond geometry to one C(1), one I(1), one I(2), one I(4), one I(8), one I(9), and two equivalent I(7) atoms. The La(4)-C(1) bond length is 2.34 Å. The La(4)-I(1) bond length is 3.27 Å. The La(4)-I(2) bond length is 3.45 Å. The La(4)-I(4) bond length is 3.45 Å. The La(4)-I(8) bond length is 3.85 Å. The La(4)-I(9) bond length is 3.72 Å. There is one shorter (3.24 Å) and one longer (3.52 Å) La(4)-I(7) bond length. In the fifth La site, La(5) is bonded in a 8-coordinate geometry to one C(1), one C(2), one I(1), one I(3), one I(4), one I(5), and two equivalent I(2) atoms. The La(5)-C(1) bond length is 2.48 Å. The La(5)-C(2) bond length is 2.55 Å. The La(5)-I(1) bond length is 3.37 Å. The La(5)-I(3) bond length is 3.36 Å. The La(5)-I(4) bond length is 3.46 Å. The La(5)-I(5) bond length is 3.36 Å. There is one shorter (3.40 Å) and one longer (3.42 Å) La(5)-I(2) bond length. There are two inequivalent C sites. In the first C site, C(1) is bonded in a 5-coordinate geometry to one La(1), one La(3), one La(4), one La(5), and one C(2) atom. The C(1)-C(2) bond length is 1.47 Å. In the second C site, C(2) is bonded in a 5-coordinate geometry to one La(1), one La(2), one La(3), one La(5), and one C(1) atom. There are nine inequivalent I sites. In the first I site, I(1) is bonded in a distorted trigonal non-coplanar geometry to one La(2), one La(4), and one La(5) atom. In the second I site, I(2) is bonded in a 4-coordinate geometry to one La(1), one La(4), and two equivalent La(5) atoms. In the third I site, I(3) is bonded in a 4-coordinate geometry to one La(1), one La(5), and two equivalent La(2) atoms. In the fourth I site, I(4) is bonded to one La(1), one La(3), one La(4), and one La(5) atom to form a mixture of distorted edge and corner-sharing ILa4 tetrahedra. In the fifth I site, I(5) is bonded in a distorted trigonal non-coplanar geometry to one La(1), one La(2), and one La(5) atom. In the sixth I site, I(6) is bonded to one La(1), one La(2), and two equivalent La(3) atoms to form a mixture of distorted edge and corner-sharing ILa4 tetrahedra. In the seventh I site, I(7) is bonded in a 3-coordinate geometry to one La(3) and two equivalent La(4) atoms. In the eighth I site, I(8) is bonded in a 3-coordinate geometry to one La(1), one La(2), and one La(4) atom. In the ninth I site, I(9) is bonded in a 4-coordinate geometry to one La(1), one La(4), and two equivalent La(3) atoms.