La6Co11Ga3 crystallizes in the tetragonal I4cm space group. There are four inequivalent La sites. In the first La site, La(1) is bonded in a 13-coordinate geometry to four equivalent Co(3), four equivalent Co(4), one Ga(1), and four equivalent Ga(2) atoms. In the second La site, La(2) is bonded in a 13-coordinate geometry to four equivalent Co(2), four equivalent Co(4), four equivalent Co(5), and one Ga(1) atom. In the third La site, La(3) is bonded in a 6-coordinate geometry to one Co(2), three equivalent Co(5), and two equivalent Ga(1) atoms. In the fourth La site, La(4) is bonded in a 6-coordinate geometry to one Co(3), two equivalent Ga(1), and three equivalent Ga(2) atoms. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent Co(2), two equivalent Co(3), two equivalent Co(5), four equivalent Co(4), and two equivalent Ga(2) atoms to form CoGa2Co10 cuboctahedra that share corners with four equivalent Co(4)La2GaCo9 cuboctahedra, faces with four equivalent Co(3)La3Ga3Co6 cuboctahedra, and faces with eight equivalent Co(4)La2GaCo9 cuboctahedra. In the second Co site, Co(2) is bonded in a 12-coordinate geometry to one La(3), two equivalent La(2), one Co(1), one Co(3), three equivalent Co(5), and four equivalent Co(4) atoms. In the third Co site, Co(3) is bonded to one La(4), two equivalent La(1), one Co(1), one Co(2), four equivalent Co(4), and three equivalent Ga(2) atoms to form distorted CoLa3Ga3Co6 cuboctahedra that share corners with two equivalent Co(3)La3Ga3Co6 cuboctahedra, edges with four equivalent Co(4)La2GaCo9 cuboctahedra, faces with two equivalent Co(1)Ga2Co10 cuboctahedra, faces with five equivalent Co(3)La3Ga3Co6 cuboctahedra, and faces with six equivalent Co(4)La2GaCo9 cuboctahedra. In the fourth Co site, Co(4) is bonded to one La(1), one La(2), one Co(1), one Co(5), two equivalent Co(2), two equivalent Co(3), three equivalent Co(4), and one Ga(2) atom to form distorted CoLa2GaCo9 cuboctahedra that share  a cornercorner with one Co(1)Ga2Co10 cuboctahedra, corners with three equivalent Co(4)La2GaCo9 cuboctahedra, edges with two equivalent Co(3)La3Ga3Co6 cuboctahedra, faces with two equivalent Co(1)Ga2Co10 cuboctahedra, faces with three equivalent Co(3)La3Ga3Co6 cuboctahedra, and faces with seven equivalent Co(4)La2GaCo9 cuboctahedra. In the fifth Co site, Co(5) is bonded in a distorted q6 geometry to two equivalent La(2), three equivalent La(3), one Co(1), one Co(5), two equivalent Co(4), and three equivalent Co(2) atoms. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a distorted q6 geometry to one La(1), one La(2), four equivalent La(3), and four equivalent La(4) atoms. In the second Ga site, Ga(2) is bonded in a 12-coordinate geometry to two equivalent La(1), three equivalent La(4), one Co(1), two equivalent Co(4), three equivalent Co(3), and one Ga(2) atom.
La6Co11Ga3 crystallizes in the tetragonal I4cm space group. There are four inequivalent La sites. In the first La site, La(1) is bonded in a 13-coordinate geometry to four equivalent Co(3), four equivalent Co(4), one Ga(1), and four equivalent Ga(2) atoms. All La(1)-Co(3) bond lengths are 3.17 Å. All La(1)-Co(4) bond lengths are 2.95 Å. The La(1)-Ga(1) bond length is 3.37 Å. All La(1)-Ga(2) bond lengths are 3.23 Å. In the second La site, La(2) is bonded in a 13-coordinate geometry to four equivalent Co(2), four equivalent Co(4), four equivalent Co(5), and one Ga(1) atom. All La(2)-Co(2) bond lengths are 3.16 Å. All La(2)-Co(4) bond lengths are 2.90 Å. All La(2)-Co(5) bond lengths are 3.29 Å. The La(2)-Ga(1) bond length is 3.36 Å. In the third La site, La(3) is bonded in a 6-coordinate geometry to one Co(2), three equivalent Co(5), and two equivalent Ga(1) atoms. The La(3)-Co(2) bond length is 2.84 Å. There are two shorter (3.12 Å) and one longer (3.30 Å) La(3)-Co(5) bond length. Both La(3)-Ga(1) bond lengths are 3.40 Å. In the fourth La site, La(4) is bonded in a 6-coordinate geometry to one Co(3), two equivalent Ga(1), and three equivalent Ga(2) atoms. The La(4)-Co(3) bond length is 2.96 Å. Both La(4)-Ga(1) bond lengths are 3.33 Å. There is one shorter (3.23 Å) and two longer (3.24 Å) La(4)-Ga(2) bond lengths. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent Co(2), two equivalent Co(3), two equivalent Co(5), four equivalent Co(4), and two equivalent Ga(2) atoms to form CoGa2Co10 cuboctahedra that share corners with four equivalent Co(4)La2GaCo9 cuboctahedra, faces with four equivalent Co(3)La3Ga3Co6 cuboctahedra, and faces with eight equivalent Co(4)La2GaCo9 cuboctahedra. Both Co(1)-Co(2) bond lengths are 2.40 Å. Both Co(1)-Co(3) bond lengths are 2.40 Å. Both Co(1)-Co(5) bond lengths are 2.36 Å. All Co(1)-Co(4) bond lengths are 2.41 Å. Both Co(1)-Ga(2) bond lengths are 2.55 Å. In the second Co site, Co(2) is bonded in a 12-coordinate geometry to one La(3), two equivalent La(2), one Co(1), one Co(3), three equivalent Co(5), and four equivalent Co(4) atoms. The Co(2)-Co(3) bond length is 2.58 Å. There is one shorter (2.50 Å) and two longer (2.54 Å) Co(2)-Co(5) bond lengths. There are two shorter (2.43 Å) and two longer (2.52 Å) Co(2)-Co(4) bond lengths. In the third Co site, Co(3) is bonded to one La(4), two equivalent La(1), one Co(1), one Co(2), four equivalent Co(4), and three equivalent Ga(2) atoms to form distorted CoLa3Ga3Co6 cuboctahedra that share corners with two equivalent Co(3)La3Ga3Co6 cuboctahedra, edges with four equivalent Co(4)La2GaCo9 cuboctahedra, faces with two equivalent Co(1)Ga2Co10 cuboctahedra, faces with five equivalent Co(3)La3Ga3Co6 cuboctahedra, and faces with six equivalent Co(4)La2GaCo9 cuboctahedra. There are two shorter (2.52 Å) and two longer (2.54 Å) Co(3)-Co(4) bond lengths. There is one shorter (2.48 Å) and two longer (2.56 Å) Co(3)-Ga(2) bond lengths. In the fourth Co site, Co(4) is bonded to one La(1), one La(2), one Co(1), one Co(5), two equivalent Co(2), two equivalent Co(3), three equivalent Co(4), and one Ga(2) atom to form distorted CoLa2GaCo9 cuboctahedra that share  a cornercorner with one Co(1)Ga2Co10 cuboctahedra, corners with three equivalent Co(4)La2GaCo9 cuboctahedra, edges with two equivalent Co(3)La3Ga3Co6 cuboctahedra, faces with two equivalent Co(1)Ga2Co10 cuboctahedra, faces with three equivalent Co(3)La3Ga3Co6 cuboctahedra, and faces with seven equivalent Co(4)La2GaCo9 cuboctahedra. The Co(4)-Co(5) bond length is 2.47 Å. There are two shorter (2.54 Å) and one longer (2.55 Å) Co(4)-Co(4) bond length. The Co(4)-Ga(2) bond length is 2.56 Å. In the fifth Co site, Co(5) is bonded in a distorted q6 geometry to two equivalent La(2), three equivalent La(3), one Co(1), one Co(5), two equivalent Co(4), and three equivalent Co(2) atoms. The Co(5)-Co(5) bond length is 2.59 Å. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a distorted q6 geometry to one La(1), one La(2), four equivalent La(3), and four equivalent La(4) atoms. In the second Ga site, Ga(2) is bonded in a 12-coordinate geometry to two equivalent La(1), three equivalent La(4), one Co(1), two equivalent Co(4), three equivalent Co(3), and one Ga(2) atom. The Ga(2)-Ga(2) bond length is 2.80 Å.