Ir3La crystallizes in the trigonal R-3m space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 12-coordinate geometry to three equivalent Ir(3) and nine equivalent Ir(1) atoms. In the second La site, La(2) is bonded in a 18-coordinate geometry to six equivalent Ir(2) and twelve equivalent Ir(1) atoms. There are three inequivalent Ir sites. In the first Ir site, Ir(1) is bonded to two equivalent La(2), three equivalent La(1), one Ir(3), two equivalent Ir(2), and four equivalent Ir(1) atoms to form IrLa5Ir7 cuboctahedra that share corners with two equivalent Ir(3)La6Ir6 cuboctahedra, corners with fifteen equivalent Ir(1)La5Ir7 cuboctahedra, edges with eight equivalent Ir(1)La5Ir7 cuboctahedra, faces with three equivalent Ir(3)La6Ir6 cuboctahedra, and faces with eleven equivalent Ir(1)La5Ir7 cuboctahedra. In the second Ir site, Ir(2) is bonded in a 9-coordinate geometry to three equivalent La(2) and six equivalent Ir(1) atoms. In the third Ir site, Ir(3) is bonded to six equivalent La(1) and six equivalent Ir(1) atoms to form IrLa6Ir6 cuboctahedra that share corners with twelve equivalent Ir(1)La5Ir7 cuboctahedra, edges with six equivalent Ir(3)La6Ir6 cuboctahedra, and faces with eighteen equivalent Ir(1)La5Ir7 cuboctahedra.
Ir3La crystallizes in the trigonal R-3m space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 12-coordinate geometry to three equivalent Ir(3) and nine equivalent Ir(1) atoms. All La(1)-Ir(3) bond lengths are 3.20 Å. There are six shorter (3.13 Å) and three longer (3.41 Å) La(1)-Ir(1) bond lengths. In the second La site, La(2) is bonded in a 18-coordinate geometry to six equivalent Ir(2) and twelve equivalent Ir(1) atoms. All La(2)-Ir(2) bond lengths are 3.11 Å. All La(2)-Ir(1) bond lengths are 3.44 Å. There are three inequivalent Ir sites. In the first Ir site, Ir(1) is bonded to two equivalent La(2), three equivalent La(1), one Ir(3), two equivalent Ir(2), and four equivalent Ir(1) atoms to form IrLa5Ir7 cuboctahedra that share corners with two equivalent Ir(3)La6Ir6 cuboctahedra, corners with fifteen equivalent Ir(1)La5Ir7 cuboctahedra, edges with eight equivalent Ir(1)La5Ir7 cuboctahedra, faces with three equivalent Ir(3)La6Ir6 cuboctahedra, and faces with eleven equivalent Ir(1)La5Ir7 cuboctahedra. The Ir(1)-Ir(3) bond length is 2.77 Å. There is one shorter (2.61 Å) and one longer (2.67 Å) Ir(1)-Ir(2) bond length. There are two shorter (2.65 Å) and two longer (2.74 Å) Ir(1)-Ir(1) bond lengths. In the second Ir site, Ir(2) is bonded in a 9-coordinate geometry to three equivalent La(2) and six equivalent Ir(1) atoms. In the third Ir site, Ir(3) is bonded to six equivalent La(1) and six equivalent Ir(1) atoms to form IrLa6Ir6 cuboctahedra that share corners with twelve equivalent Ir(1)La5Ir7 cuboctahedra, edges with six equivalent Ir(3)La6Ir6 cuboctahedra, and faces with eighteen equivalent Ir(1)La5Ir7 cuboctahedra.