PrCu4Al crystallizes in the hexagonal P-6m2 space group. Pr(1) is bonded in a 18-coordinate geometry to three equivalent Cu(1), twelve equivalent Cu(2), and three equivalent Al(1) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to three equivalent Pr(1), six equivalent Cu(2), and three equivalent Al(1) atoms to form distorted CuPr3Al3Cu6 cuboctahedra that share corners with twelve equivalent Cu(2)Pr4Al2Cu6 cuboctahedra, edges with six equivalent Cu(1)Pr3Al3Cu6 cuboctahedra, faces with two equivalent Cu(1)Pr3Al3Cu6 cuboctahedra, and faces with eighteen equivalent Cu(2)Pr4Al2Cu6 cuboctahedra. In the second Cu site, Cu(2) is bonded to four equivalent Pr(1), two equivalent Cu(1), four equivalent Cu(2), and two equivalent Al(1) atoms to form distorted CuPr4Al2Cu6 cuboctahedra that share corners with four equivalent Cu(1)Pr3Al3Cu6 cuboctahedra, corners with sixteen equivalent Cu(2)Pr4Al2Cu6 cuboctahedra, edges with ten equivalent Cu(2)Pr4Al2Cu6 cuboctahedra, faces with six equivalent Cu(1)Pr3Al3Cu6 cuboctahedra, and faces with ten equivalent Cu(2)Pr4Al2Cu6 cuboctahedra. Al(1) is bonded in a 12-coordinate geometry to three equivalent Pr(1), three equivalent Cu(1), and six equivalent Cu(2) atoms.
PrCu4Al crystallizes in the hexagonal P-6m2 space group. Pr(1) is bonded in a 18-coordinate geometry to three equivalent Cu(1), twelve equivalent Cu(2), and three equivalent Al(1) atoms. All Pr(1)-Cu(1) bond lengths are 3.08 Å. All Pr(1)-Cu(2) bond lengths are 3.35 Å. All Pr(1)-Al(1) bond lengths are 3.08 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to three equivalent Pr(1), six equivalent Cu(2), and three equivalent Al(1) atoms to form distorted CuPr3Al3Cu6 cuboctahedra that share corners with twelve equivalent Cu(2)Pr4Al2Cu6 cuboctahedra, edges with six equivalent Cu(1)Pr3Al3Cu6 cuboctahedra, faces with two equivalent Cu(1)Pr3Al3Cu6 cuboctahedra, and faces with eighteen equivalent Cu(2)Pr4Al2Cu6 cuboctahedra. All Cu(1)-Cu(2) bond lengths are 2.53 Å. All Cu(1)-Al(1) bond lengths are 3.08 Å. In the second Cu site, Cu(2) is bonded to four equivalent Pr(1), two equivalent Cu(1), four equivalent Cu(2), and two equivalent Al(1) atoms to form distorted CuPr4Al2Cu6 cuboctahedra that share corners with four equivalent Cu(1)Pr3Al3Cu6 cuboctahedra, corners with sixteen equivalent Cu(2)Pr4Al2Cu6 cuboctahedra, edges with ten equivalent Cu(2)Pr4Al2Cu6 cuboctahedra, faces with six equivalent Cu(1)Pr3Al3Cu6 cuboctahedra, and faces with ten equivalent Cu(2)Pr4Al2Cu6 cuboctahedra. There are two shorter (2.66 Å) and two longer (2.69 Å) Cu(2)-Cu(2) bond lengths. Both Cu(2)-Al(1) bond lengths are 2.54 Å. Al(1) is bonded in a 12-coordinate geometry to three equivalent Pr(1), three equivalent Cu(1), and six equivalent Cu(2) atoms.