La20Os12C13 crystallizes in the monoclinic P2/m space group. There are eight inequivalent La sites. In the first La site, La(1) is bonded in a 5-coordinate geometry to two equivalent Os(3), one C(2), one C(5), and one C(7) atom. In the second La site, La(2) is bonded in a 4-coordinate geometry to two equivalent Os(4), one C(1), and one C(4) atom. In the third La site, La(3) is bonded in a 4-coordinate geometry to one Os(2), one Os(4), one C(3), and one C(6) atom. In the fourth La site, La(4) is bonded in a 5-coordinate geometry to one Os(1), one Os(3), one C(3), one C(6), and one C(7) atom. In the fifth La site, La(5) is bonded in a trigonal planar geometry to one C(1) and two equivalent C(3) atoms. In the sixth La site, La(6) is bonded in a trigonal planar geometry to one C(2) and two equivalent C(3) atoms. In the seventh La site, La(7) is bonded in a trigonal planar geometry to one C(5) and two equivalent C(6) atoms. In the eighth La site, La(8) is bonded in a trigonal planar geometry to one C(4) and two equivalent C(6) atoms. There are four inequivalent Os sites. In the first Os site, Os(1) is bonded in a distorted bent 120 degrees geometry to two equivalent La(4), one C(2), and one C(5) atom. In the second Os site, Os(2) is bonded in a distorted bent 120 degrees geometry to two equivalent La(3), one C(1), and one C(4) atom. In the third Os site, Os(3) is bonded in a distorted bent 120 degrees geometry to one La(1), one La(4), one C(3), and one C(6) atom. In the fourth Os site, Os(4) is bonded in a distorted bent 120 degrees geometry to one La(2), one La(3), one C(3), and one C(6) atom. There are seven inequivalent C sites. In the first C site, C(1) is bonded to two equivalent La(2), two equivalent La(5), and two equivalent Os(2) atoms to form a mixture of corner and edge-sharing CLa4Os2 octahedra. The corner-sharing octahedral tilt angles are 60°. In the second C site, C(2) is bonded to two equivalent La(1), two equivalent La(6), and two equivalent Os(1) atoms to form CLa4Os2 octahedra that share corners with two equivalent C(7)La6 octahedra, corners with four equivalent C(3)La4Os2 octahedra, and edges with two equivalent C(5)La4Os2 octahedra. The corner-sharing octahedral tilt angles range from 60-70°. In the third C site, C(3) is bonded to one La(3), one La(4), one La(5), one La(6), one Os(3), and one Os(4) atom to form CLa4Os2 octahedra that share  a cornercorner with one C(1)La4Os2 octahedra,  a cornercorner with one C(2)La4Os2 octahedra,  a cornercorner with one C(7)La6 octahedra, corners with two equivalent C(3)La4Os2 octahedra, and edges with two equivalent C(6)La4Os2 octahedra. The corner-sharing octahedral tilt angles range from 60-69°. In the fourth C site, C(4) is bonded to two equivalent La(2), two equivalent La(8), and two equivalent Os(2) atoms to form a mixture of corner and edge-sharing CLa4Os2 octahedra. The corner-sharing octahedral tilt angles are 60°. In the fifth C site, C(5) is bonded to two equivalent La(1), two equivalent La(7), and two equivalent Os(1) atoms to form CLa4Os2 octahedra that share corners with two equivalent C(7)La6 octahedra, corners with four equivalent C(6)La4Os2 octahedra, and edges with two equivalent C(2)La4Os2 octahedra. The corner-sharing octahedral tilt angles range from 1-60°. In the sixth C site, C(6) is bonded to one La(3), one La(4), one La(7), one La(8), one Os(3), and one Os(4) atom to form CLa4Os2 octahedra that share  a cornercorner with one C(4)La4Os2 octahedra,  a cornercorner with one C(5)La4Os2 octahedra,  a cornercorner with one C(7)La6 octahedra, corners with two equivalent C(6)La4Os2 octahedra, and edges with two equivalent C(3)La4Os2 octahedra. The corner-sharing octahedral tilt angles range from 1-61°. In the seventh C site, C(7) is bonded to two equivalent La(1) and four equivalent La(4) atoms to form corner-sharing CLa6 octahedra. The corner-sharing octahedral tilt angles range from 1-70°.
La20Os12C13 crystallizes in the monoclinic P2/m space group. There are eight inequivalent La sites. In the first La site, La(1) is bonded in a 5-coordinate geometry to two equivalent Os(3), one C(2), one C(5), and one C(7) atom. Both La(1)-Os(3) bond lengths are 3.26 Å. The La(1)-C(2) bond length is 2.88 Å. The La(1)-C(5) bond length is 3.00 Å. The La(1)-C(7) bond length is 2.71 Å. In the second La site, La(2) is bonded in a 4-coordinate geometry to two equivalent Os(4), one C(1), and one C(4) atom. Both La(2)-Os(4) bond lengths are 3.24 Å. The La(2)-C(1) bond length is 2.85 Å. The La(2)-C(4) bond length is 2.83 Å. In the third La site, La(3) is bonded in a 4-coordinate geometry to one Os(2), one Os(4), one C(3), and one C(6) atom. The La(3)-Os(2) bond length is 3.24 Å. The La(3)-Os(4) bond length is 3.22 Å. The La(3)-C(3) bond length is 2.86 Å. The La(3)-C(6) bond length is 2.85 Å. In the fourth La site, La(4) is bonded in a 5-coordinate geometry to one Os(1), one Os(3), one C(3), one C(6), and one C(7) atom. The La(4)-Os(1) bond length is 3.23 Å. The La(4)-Os(3) bond length is 3.24 Å. The La(4)-C(3) bond length is 2.89 Å. The La(4)-C(6) bond length is 3.02 Å. The La(4)-C(7) bond length is 2.72 Å. In the fifth La site, La(5) is bonded in a trigonal planar geometry to one C(1) and two equivalent C(3) atoms. The La(5)-C(1) bond length is 2.66 Å. Both La(5)-C(3) bond lengths are 2.65 Å. In the sixth La site, La(6) is bonded in a trigonal planar geometry to one C(2) and two equivalent C(3) atoms. The La(6)-C(2) bond length is 2.66 Å. Both La(6)-C(3) bond lengths are 2.66 Å. In the seventh La site, La(7) is bonded in a trigonal planar geometry to one C(5) and two equivalent C(6) atoms. The La(7)-C(5) bond length is 2.65 Å. Both La(7)-C(6) bond lengths are 2.65 Å. In the eighth La site, La(8) is bonded in a trigonal planar geometry to one C(4) and two equivalent C(6) atoms. The La(8)-C(4) bond length is 2.67 Å. Both La(8)-C(6) bond lengths are 2.65 Å. There are four inequivalent Os sites. In the first Os site, Os(1) is bonded in a distorted bent 120 degrees geometry to two equivalent La(4), one C(2), and one C(5) atom. The Os(1)-C(2) bond length is 1.92 Å. The Os(1)-C(5) bond length is 1.91 Å. In the second Os site, Os(2) is bonded in a distorted bent 120 degrees geometry to two equivalent La(3), one C(1), and one C(4) atom. The Os(2)-C(1) bond length is 1.93 Å. The Os(2)-C(4) bond length is 1.93 Å. In the third Os site, Os(3) is bonded in a distorted bent 120 degrees geometry to one La(1), one La(4), one C(3), and one C(6) atom. The Os(3)-C(3) bond length is 1.93 Å. The Os(3)-C(6) bond length is 1.92 Å. In the fourth Os site, Os(4) is bonded in a distorted bent 120 degrees geometry to one La(2), one La(3), one C(3), and one C(6) atom. The Os(4)-C(3) bond length is 1.92 Å. The Os(4)-C(6) bond length is 1.92 Å. There are seven inequivalent C sites. In the first C site, C(1) is bonded to two equivalent La(2), two equivalent La(5), and two equivalent Os(2) atoms to form a mixture of corner and edge-sharing CLa4Os2 octahedra. The corner-sharing octahedral tilt angles are 60°. In the second C site, C(2) is bonded to two equivalent La(1), two equivalent La(6), and two equivalent Os(1) atoms to form CLa4Os2 octahedra that share corners with two equivalent C(7)La6 octahedra, corners with four equivalent C(3)La4Os2 octahedra, and edges with two equivalent C(5)La4Os2 octahedra. The corner-sharing octahedral tilt angles range from 60-70°. In the third C site, C(3) is bonded to one La(3), one La(4), one La(5), one La(6), one Os(3), and one Os(4) atom to form CLa4Os2 octahedra that share  a cornercorner with one C(1)La4Os2 octahedra,  a cornercorner with one C(2)La4Os2 octahedra,  a cornercorner with one C(7)La6 octahedra, corners with two equivalent C(3)La4Os2 octahedra, and edges with two equivalent C(6)La4Os2 octahedra. The corner-sharing octahedral tilt angles range from 60-69°. In the fourth C site, C(4) is bonded to two equivalent La(2), two equivalent La(8), and two equivalent Os(2) atoms to form a mixture of corner and edge-sharing CLa4Os2 octahedra. The corner-sharing octahedral tilt angles are 60°. In the fifth C site, C(5) is bonded to two equivalent La(1), two equivalent La(7), and two equivalent Os(1) atoms to form CLa4Os2 octahedra that share corners with two equivalent C(7)La6 octahedra, corners with four equivalent C(6)La4Os2 octahedra, and edges with two equivalent C(2)La4Os2 octahedra. The corner-sharing octahedral tilt angles range from 1-60°. In the sixth C site, C(6) is bonded to one La(3), one La(4), one La(7), one La(8), one Os(3), and one Os(4) atom to form CLa4Os2 octahedra that share  a cornercorner with one C(4)La4Os2 octahedra,  a cornercorner with one C(5)La4Os2 octahedra,  a cornercorner with one C(7)La6 octahedra, corners with two equivalent C(6)La4Os2 octahedra, and edges with two equivalent C(3)La4Os2 octahedra. The corner-sharing octahedral tilt angles range from 1-61°. In the seventh C site, C(7) is bonded to two equivalent La(1) and four equivalent La(4) atoms to form corner-sharing CLa6 octahedra. The corner-sharing octahedral tilt angles range from 1-70°.