La10C4I15 crystallizes in the triclinic P-1 space group. There are five inequivalent La sites. In the first La site, La(1) is bonded to one C(2), one I(2), one I(3), one I(5), and two equivalent I(6) atoms to form distorted LaCI5 octahedra that share  a cornercorner with one La(2)C2I5 pentagonal bipyramid,  a cornercorner with one La(3)C2I5 pentagonal bipyramid,  an edgeedge with one La(1)CI5 octahedra,  an edgeedge with one La(4)CI5 octahedra,  an edgeedge with one La(2)C2I5 pentagonal bipyramid, and  an edgeedge with one La(3)C2I5 pentagonal bipyramid. In the second La site, La(2) is bonded to one C(1), one C(2), one I(1), one I(4), one I(6), one I(7), and one I(8) atom to form distorted LaC2I5 pentagonal bipyramids that share  a cornercorner with one La(1)CI5 octahedra,  a cornercorner with one La(2)C2I5 pentagonal bipyramid, corners with two equivalent La(3)C2I5 pentagonal bipyramids,  an edgeedge with one La(1)CI5 octahedra, edges with two equivalent La(4)CI5 octahedra, and  a faceface with one La(3)C2I5 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 12°. In the third La site, La(3) is bonded to one C(1), one C(2), one I(1), one I(4), one I(7), and two equivalent I(2) atoms to form distorted LaC2I5 pentagonal bipyramids that share  a cornercorner with one La(1)CI5 octahedra, corners with two equivalent La(2)C2I5 pentagonal bipyramids,  an edgeedge with one La(1)CI5 octahedra, edges with two equivalent La(4)CI5 octahedra,  an edgeedge with one La(3)C2I5 pentagonal bipyramid, and  a faceface with one La(2)C2I5 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 1°. In the fourth La site, La(4) is bonded to one C(1), one I(3), one I(4), one I(5), and two equivalent I(1) atoms to form distorted LaCI5 octahedra that share  an edgeedge with one La(1)CI5 octahedra,  an edgeedge with one La(4)CI5 octahedra, edges with two equivalent La(2)C2I5 pentagonal bipyramids, and edges with two equivalent La(3)C2I5 pentagonal bipyramids. In the fifth La site, La(5) is bonded in a 8-coordinate geometry to two equivalent C(1), two equivalent C(2), one I(3), one I(5), one I(7), and one I(8) atom. There are two inequivalent C sites. In the first C site, C(1) is bonded in a 6-coordinate geometry to one La(2), one La(3), one La(4), two equivalent La(5), and one C(2) atom. In the second C site, C(2) is bonded in a 6-coordinate geometry to one La(1), one La(2), one La(3), two equivalent La(5), and one C(1) atom. There are eight inequivalent I sites. In the first I site, I(1) is bonded in a rectangular see-saw-like geometry to one La(2), one La(3), and two equivalent La(4) atoms. In the second I site, I(2) is bonded in a distorted T-shaped geometry to one La(1) and two equivalent La(3) atoms. In the third I site, I(3) is bonded in a distorted T-shaped geometry to one La(1), one La(4), and one La(5) atom. In the fourth I site, I(4) is bonded in a distorted T-shaped geometry to one La(2), one La(3), and one La(4) atom. In the fifth I site, I(5) is bonded in a distorted T-shaped geometry to one La(1), one La(4), and one La(5) atom. In the sixth I site, I(6) is bonded in a T-shaped geometry to one La(2) and two equivalent La(1) atoms. In the seventh I site, I(7) is bonded in a 3-coordinate geometry to one La(2), one La(3), and one La(5) atom. In the eighth I site, I(8) is bonded in a distorted rectangular see-saw-like geometry to two equivalent La(2) and two equivalent La(5) atoms.
La10C4I15 crystallizes in the triclinic P-1 space group. There are five inequivalent La sites. In the first La site, La(1) is bonded to one C(2), one I(2), one I(3), one I(5), and two equivalent I(6) atoms to form distorted LaCI5 octahedra that share  a cornercorner with one La(2)C2I5 pentagonal bipyramid,  a cornercorner with one La(3)C2I5 pentagonal bipyramid,  an edgeedge with one La(1)CI5 octahedra,  an edgeedge with one La(4)CI5 octahedra,  an edgeedge with one La(2)C2I5 pentagonal bipyramid, and  an edgeedge with one La(3)C2I5 pentagonal bipyramid. The La(1)-C(2) bond length is 2.36 Å. The La(1)-I(2) bond length is 3.23 Å. The La(1)-I(3) bond length is 3.23 Å. The La(1)-I(5) bond length is 3.24 Å. There is one shorter (3.23 Å) and one longer (3.47 Å) La(1)-I(6) bond length. In the second La site, La(2) is bonded to one C(1), one C(2), one I(1), one I(4), one I(6), one I(7), and one I(8) atom to form distorted LaC2I5 pentagonal bipyramids that share  a cornercorner with one La(1)CI5 octahedra,  a cornercorner with one La(2)C2I5 pentagonal bipyramid, corners with two equivalent La(3)C2I5 pentagonal bipyramids,  an edgeedge with one La(1)CI5 octahedra, edges with two equivalent La(4)CI5 octahedra, and  a faceface with one La(3)C2I5 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 12°. The La(2)-C(1) bond length is 2.64 Å. The La(2)-C(2) bond length is 2.64 Å. The La(2)-I(1) bond length is 3.37 Å. The La(2)-I(4) bond length is 3.20 Å. The La(2)-I(6) bond length is 3.27 Å. The La(2)-I(7) bond length is 3.55 Å. The La(2)-I(8) bond length is 3.21 Å. In the third La site, La(3) is bonded to one C(1), one C(2), one I(1), one I(4), one I(7), and two equivalent I(2) atoms to form distorted LaC2I5 pentagonal bipyramids that share  a cornercorner with one La(1)CI5 octahedra, corners with two equivalent La(2)C2I5 pentagonal bipyramids,  an edgeedge with one La(1)CI5 octahedra, edges with two equivalent La(4)CI5 octahedra,  an edgeedge with one La(3)C2I5 pentagonal bipyramid, and  a faceface with one La(2)C2I5 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 1°. The La(3)-C(1) bond length is 2.67 Å. The La(3)-C(2) bond length is 2.66 Å. The La(3)-I(1) bond length is 3.36 Å. The La(3)-I(4) bond length is 3.26 Å. The La(3)-I(7) bond length is 3.17 Å. There is one shorter (3.25 Å) and one longer (3.53 Å) La(3)-I(2) bond length. In the fourth La site, La(4) is bonded to one C(1), one I(3), one I(4), one I(5), and two equivalent I(1) atoms to form distorted LaCI5 octahedra that share  an edgeedge with one La(1)CI5 octahedra,  an edgeedge with one La(4)CI5 octahedra, edges with two equivalent La(2)C2I5 pentagonal bipyramids, and edges with two equivalent La(3)C2I5 pentagonal bipyramids. The La(4)-C(1) bond length is 2.36 Å. The La(4)-I(3) bond length is 3.24 Å. The La(4)-I(4) bond length is 3.45 Å. The La(4)-I(5) bond length is 3.23 Å. There is one shorter (3.31 Å) and one longer (3.32 Å) La(4)-I(1) bond length. In the fifth La site, La(5) is bonded in a 8-coordinate geometry to two equivalent C(1), two equivalent C(2), one I(3), one I(5), one I(7), and one I(8) atom. There is one shorter (2.76 Å) and one longer (2.81 Å) La(5)-C(1) bond length. There is one shorter (2.78 Å) and one longer (2.82 Å) La(5)-C(2) bond length. The La(5)-I(3) bond length is 3.33 Å. The La(5)-I(5) bond length is 3.32 Å. The La(5)-I(7) bond length is 3.38 Å. The La(5)-I(8) bond length is 3.45 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded in a 6-coordinate geometry to one La(2), one La(3), one La(4), two equivalent La(5), and one C(2) atom. The C(1)-C(2) bond length is 1.41 Å. In the second C site, C(2) is bonded in a 6-coordinate geometry to one La(1), one La(2), one La(3), two equivalent La(5), and one C(1) atom. There are eight inequivalent I sites. In the first I site, I(1) is bonded in a rectangular see-saw-like geometry to one La(2), one La(3), and two equivalent La(4) atoms. In the second I site, I(2) is bonded in a distorted T-shaped geometry to one La(1) and two equivalent La(3) atoms. In the third I site, I(3) is bonded in a distorted T-shaped geometry to one La(1), one La(4), and one La(5) atom. In the fourth I site, I(4) is bonded in a distorted T-shaped geometry to one La(2), one La(3), and one La(4) atom. In the fifth I site, I(5) is bonded in a distorted T-shaped geometry to one La(1), one La(4), and one La(5) atom. In the sixth I site, I(6) is bonded in a T-shaped geometry to one La(2) and two equivalent La(1) atoms. In the seventh I site, I(7) is bonded in a 3-coordinate geometry to one La(2), one La(3), and one La(5) atom. In the eighth I site, I(8) is bonded in a distorted rectangular see-saw-like geometry to two equivalent La(2) and two equivalent La(5) atoms.