Cu3Mn2Al crystallizes in the trigonal R-3m space group. Mn(1) is bonded in a 16-coordinate geometry to four equivalent Mn(1), nine equivalent Cu(1), and three equivalent Al(1) atoms. Cu(1) is bonded to six equivalent Mn(1), four equivalent Cu(1), and two equivalent Al(1) atoms to form CuMn6Al2Cu4 cuboctahedra that share corners with four equivalent Al(1)Mn6Cu6 cuboctahedra, corners with fourteen equivalent Cu(1)Mn6Al2Cu4 cuboctahedra, edges with six equivalent Cu(1)Mn6Al2Cu4 cuboctahedra, faces with six equivalent Al(1)Mn6Cu6 cuboctahedra, and faces with twelve equivalent Cu(1)Mn6Al2Cu4 cuboctahedra. Al(1) is bonded to six equivalent Mn(1) and six equivalent Cu(1) atoms to form distorted AlMn6Cu6 cuboctahedra that share corners with six equivalent Al(1)Mn6Cu6 cuboctahedra, corners with twelve equivalent Cu(1)Mn6Al2Cu4 cuboctahedra, edges with six equivalent Al(1)Mn6Cu6 cuboctahedra, and faces with eighteen equivalent Cu(1)Mn6Al2Cu4 cuboctahedra.
Cu3Mn2Al crystallizes in the trigonal R-3m space group. Mn(1) is bonded in a 16-coordinate geometry to four equivalent Mn(1), nine equivalent Cu(1), and three equivalent Al(1) atoms. There are three shorter (2.95 Å) and one longer (3.00 Å) Mn(1)-Mn(1) bond length. There are three shorter (2.83 Å) and six longer (2.84 Å) Mn(1)-Cu(1) bond lengths. All Mn(1)-Al(1) bond lengths are 2.83 Å. Cu(1) is bonded to six equivalent Mn(1), four equivalent Cu(1), and two equivalent Al(1) atoms to form CuMn6Al2Cu4 cuboctahedra that share corners with four equivalent Al(1)Mn6Cu6 cuboctahedra, corners with fourteen equivalent Cu(1)Mn6Al2Cu4 cuboctahedra, edges with six equivalent Cu(1)Mn6Al2Cu4 cuboctahedra, faces with six equivalent Al(1)Mn6Cu6 cuboctahedra, and faces with twelve equivalent Cu(1)Mn6Al2Cu4 cuboctahedra. All Cu(1)-Cu(1) bond lengths are 2.42 Å. Both Cu(1)-Al(1) bond lengths are 2.43 Å. Al(1) is bonded to six equivalent Mn(1) and six equivalent Cu(1) atoms to form distorted AlMn6Cu6 cuboctahedra that share corners with six equivalent Al(1)Mn6Cu6 cuboctahedra, corners with twelve equivalent Cu(1)Mn6Al2Cu4 cuboctahedra, edges with six equivalent Al(1)Mn6Cu6 cuboctahedra, and faces with eighteen equivalent Cu(1)Mn6Al2Cu4 cuboctahedra.