Pr2(CuAl)5 crystallizes in the orthorhombic Pmmm space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 18-coordinate geometry to eight equivalent Cu(2), two equivalent Al(1), four equivalent Al(2), and four equivalent Al(3) atoms. In the second Pr site, Pr(2) is bonded in a 18-coordinate geometry to four equivalent Cu(1), eight equivalent Cu(2), two equivalent Al(2), and four equivalent Al(1) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to four equivalent Pr(2), four equivalent Cu(2), and four equivalent Al(1) atoms to form distorted CuPr4Al4Cu4 cuboctahedra that share corners with four equivalent Cu(1)Pr4Al4Cu4 cuboctahedra, corners with four equivalent Al(3)Pr4Al4Cu4 cuboctahedra, edges with two equivalent Cu(1)Pr4Al4Cu4 cuboctahedra, and faces with two equivalent Cu(1)Pr4Al4Cu4 cuboctahedra. In the second Cu site, Cu(2) is bonded in a 12-coordinate geometry to two equivalent Pr(1), two equivalent Pr(2), one Cu(1), two equivalent Cu(2), one Al(3), two equivalent Al(1), and two equivalent Al(2) atoms. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 9-coordinate geometry to one Pr(1), two equivalent Pr(2), two equivalent Cu(1), and four equivalent Cu(2) atoms. In the second Al site, Al(2) is bonded in a 9-coordinate geometry to one Pr(2), two equivalent Pr(1), four equivalent Cu(2), and two equivalent Al(3) atoms. In the third Al site, Al(3) is bonded to four equivalent Pr(1), four equivalent Cu(2), and four equivalent Al(2) atoms to form AlPr4Al4Cu4 cuboctahedra that share corners with four equivalent Cu(1)Pr4Al4Cu4 cuboctahedra, corners with four equivalent Al(3)Pr4Al4Cu4 cuboctahedra, edges with two equivalent Al(3)Pr4Al4Cu4 cuboctahedra, and faces with two equivalent Al(3)Pr4Al4Cu4 cuboctahedra.
Pr2(CuAl)5 crystallizes in the orthorhombic Pmmm space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 18-coordinate geometry to eight equivalent Cu(2), two equivalent Al(1), four equivalent Al(2), and four equivalent Al(3) atoms. All Pr(1)-Cu(2) bond lengths are 3.40 Å. Both Pr(1)-Al(1) bond lengths are 3.19 Å. All Pr(1)-Al(2) bond lengths are 3.19 Å. All Pr(1)-Al(3) bond lengths are 3.34 Å. In the second Pr site, Pr(2) is bonded in a 18-coordinate geometry to four equivalent Cu(1), eight equivalent Cu(2), two equivalent Al(2), and four equivalent Al(1) atoms. All Pr(2)-Cu(1) bond lengths are 3.34 Å. All Pr(2)-Cu(2) bond lengths are 3.43 Å. Both Pr(2)-Al(2) bond lengths are 3.02 Å. All Pr(2)-Al(1) bond lengths are 3.10 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to four equivalent Pr(2), four equivalent Cu(2), and four equivalent Al(1) atoms to form distorted CuPr4Al4Cu4 cuboctahedra that share corners with four equivalent Cu(1)Pr4Al4Cu4 cuboctahedra, corners with four equivalent Al(3)Pr4Al4Cu4 cuboctahedra, edges with two equivalent Cu(1)Pr4Al4Cu4 cuboctahedra, and faces with two equivalent Cu(1)Pr4Al4Cu4 cuboctahedra. All Cu(1)-Cu(2) bond lengths are 2.75 Å. All Cu(1)-Al(1) bond lengths are 2.60 Å. In the second Cu site, Cu(2) is bonded in a 12-coordinate geometry to two equivalent Pr(1), two equivalent Pr(2), one Cu(1), two equivalent Cu(2), one Al(3), two equivalent Al(1), and two equivalent Al(2) atoms. There is one shorter (2.61 Å) and one longer (2.68 Å) Cu(2)-Cu(2) bond length. The Cu(2)-Al(3) bond length is 2.73 Å. Both Cu(2)-Al(1) bond lengths are 2.55 Å. Both Cu(2)-Al(2) bond lengths are 2.51 Å. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 9-coordinate geometry to one Pr(1), two equivalent Pr(2), two equivalent Cu(1), and four equivalent Cu(2) atoms. In the second Al site, Al(2) is bonded in a 9-coordinate geometry to one Pr(2), two equivalent Pr(1), four equivalent Cu(2), and two equivalent Al(3) atoms. Both Al(2)-Al(3) bond lengths are 2.71 Å. In the third Al site, Al(3) is bonded to four equivalent Pr(1), four equivalent Cu(2), and four equivalent Al(2) atoms to form AlPr4Al4Cu4 cuboctahedra that share corners with four equivalent Cu(1)Pr4Al4Cu4 cuboctahedra, corners with four equivalent Al(3)Pr4Al4Cu4 cuboctahedra, edges with two equivalent Al(3)Pr4Al4Cu4 cuboctahedra, and faces with two equivalent Al(3)Pr4Al4Cu4 cuboctahedra.