PuAl3 crystallizes in the trigonal R-3m space group. There are two inequivalent Pu sites. In the first Pu site, Pu(1) is bonded to six equivalent Al(1) and six equivalent Al(2) atoms to form PuAl12 cuboctahedra that share corners with six equivalent Pu(1)Al12 cuboctahedra, edges with six equivalent Al(1)Pu4Al8 cuboctahedra, faces with six equivalent Al(1)Pu4Al8 cuboctahedra, and faces with eight equivalent Pu(2)Al12 cuboctahedra. In the second Pu site, Pu(2) is bonded to three equivalent Al(1) and nine equivalent Al(2) atoms to form PuAl12 cuboctahedra that share corners with six equivalent Al(1)Pu4Al8 cuboctahedra, corners with nine equivalent Pu(2)Al12 cuboctahedra, edges with six equivalent Al(1)Pu4Al8 cuboctahedra, faces with three equivalent Pu(2)Al12 cuboctahedra, faces with three equivalent Al(1)Pu4Al8 cuboctahedra, and faces with four equivalent Pu(1)Al12 cuboctahedra. There are two inequivalent Al sites. In the first Al site, Al(2) is bonded in a 10-coordinate geometry to one Pu(1), three equivalent Pu(2), two equivalent Al(1), and four equivalent Al(2) atoms. In the second Al site, Al(1) is bonded to two equivalent Pu(1), two equivalent Pu(2), four equivalent Al(1), and four equivalent Al(2) atoms to form distorted AlPu4Al8 cuboctahedra that share corners with four equivalent Pu(2)Al12 cuboctahedra, corners with six equivalent Al(1)Pu4Al8 cuboctahedra, edges with two equivalent Pu(1)Al12 cuboctahedra, edges with four equivalent Pu(2)Al12 cuboctahedra, edges with four equivalent Al(1)Pu4Al8 cuboctahedra, faces with two equivalent Pu(1)Al12 cuboctahedra, faces with two equivalent Pu(2)Al12 cuboctahedra, and faces with four equivalent Al(1)Pu4Al8 cuboctahedra.
PuAl3 crystallizes in the trigonal R-3m space group. There are two inequivalent Pu sites. In the first Pu site, Pu(1) is bonded to six equivalent Al(1) and six equivalent Al(2) atoms to form PuAl12 cuboctahedra that share corners with six equivalent Pu(1)Al12 cuboctahedra, edges with six equivalent Al(1)Pu4Al8 cuboctahedra, faces with six equivalent Al(1)Pu4Al8 cuboctahedra, and faces with eight equivalent Pu(2)Al12 cuboctahedra. All Pu(1)-Al(1) bond lengths are 3.07 Å. All Pu(1)-Al(2) bond lengths are 3.04 Å. In the second Pu site, Pu(2) is bonded to three equivalent Al(1) and nine equivalent Al(2) atoms to form PuAl12 cuboctahedra that share corners with six equivalent Al(1)Pu4Al8 cuboctahedra, corners with nine equivalent Pu(2)Al12 cuboctahedra, edges with six equivalent Al(1)Pu4Al8 cuboctahedra, faces with three equivalent Pu(2)Al12 cuboctahedra, faces with three equivalent Al(1)Pu4Al8 cuboctahedra, and faces with four equivalent Pu(1)Al12 cuboctahedra. All Pu(2)-Al(1) bond lengths are 3.01 Å. There are three shorter (3.00 Å) and six longer (3.08 Å) Pu(2)-Al(2) bond lengths. There are two inequivalent Al sites. In the first Al site, Al(2) is bonded in a 10-coordinate geometry to one Pu(1), three equivalent Pu(2), two equivalent Al(1), and four equivalent Al(2) atoms. Both Al(2)-Al(1) bond lengths are 2.89 Å. There are two shorter (2.79 Å) and two longer (2.87 Å) Al(2)-Al(2) bond lengths. In the second Al site, Al(1) is bonded to two equivalent Pu(1), two equivalent Pu(2), four equivalent Al(1), and four equivalent Al(2) atoms to form distorted AlPu4Al8 cuboctahedra that share corners with four equivalent Pu(2)Al12 cuboctahedra, corners with six equivalent Al(1)Pu4Al8 cuboctahedra, edges with two equivalent Pu(1)Al12 cuboctahedra, edges with four equivalent Pu(2)Al12 cuboctahedra, edges with four equivalent Al(1)Pu4Al8 cuboctahedra, faces with two equivalent Pu(1)Al12 cuboctahedra, faces with two equivalent Pu(2)Al12 cuboctahedra, and faces with four equivalent Al(1)Pu4Al8 cuboctahedra. All Al(1)-Al(1) bond lengths are 3.07 Å.