NdPrAl6 crystallizes in the hexagonal P-6m2 space group. Nd(1) is bonded to six equivalent Al(1) and six equivalent Al(2) atoms to form distorted NdAl12 cuboctahedra that share corners with six equivalent Nd(1)Al12 cuboctahedra, faces with two equivalent Nd(1)Al12 cuboctahedra, and faces with six equivalent Pr(1)Al12 cuboctahedra. Pr(1) is bonded to six equivalent Al(1) and six equivalent Al(2) atoms to form distorted PrAl12 cuboctahedra that share corners with six equivalent Pr(1)Al12 cuboctahedra, faces with two equivalent Pr(1)Al12 cuboctahedra, and faces with six equivalent Nd(1)Al12 cuboctahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 10-coordinate geometry to two equivalent Nd(1), two equivalent Pr(1), two equivalent Al(1), and four equivalent Al(2) atoms. In the second Al site, Al(2) is bonded in a 10-coordinate geometry to two equivalent Nd(1), two equivalent Pr(1), two equivalent Al(2), and four equivalent Al(1) atoms.
NdPrAl6 crystallizes in the hexagonal P-6m2 space group. Nd(1) is bonded to six equivalent Al(1) and six equivalent Al(2) atoms to form distorted NdAl12 cuboctahedra that share corners with six equivalent Nd(1)Al12 cuboctahedra, faces with two equivalent Nd(1)Al12 cuboctahedra, and faces with six equivalent Pr(1)Al12 cuboctahedra. All Nd(1)-Al(1) bond lengths are 3.29 Å. All Nd(1)-Al(2) bond lengths are 3.18 Å. Pr(1) is bonded to six equivalent Al(1) and six equivalent Al(2) atoms to form distorted PrAl12 cuboctahedra that share corners with six equivalent Pr(1)Al12 cuboctahedra, faces with two equivalent Pr(1)Al12 cuboctahedra, and faces with six equivalent Nd(1)Al12 cuboctahedra. All Pr(1)-Al(1) bond lengths are 3.19 Å. All Pr(1)-Al(2) bond lengths are 3.29 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 10-coordinate geometry to two equivalent Nd(1), two equivalent Pr(1), two equivalent Al(1), and four equivalent Al(2) atoms. Both Al(1)-Al(1) bond lengths are 2.72 Å. All Al(1)-Al(2) bond lengths are 2.79 Å. In the second Al site, Al(2) is bonded in a 10-coordinate geometry to two equivalent Nd(1), two equivalent Pr(1), two equivalent Al(2), and four equivalent Al(1) atoms. Both Al(2)-Al(2) bond lengths are 2.73 Å.