Al11Nd3 crystallizes in the orthorhombic Immm space group. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded to four equivalent Al(2), four equivalent Al(4), and eight equivalent Al(3) atoms to form distorted NdAl16 cuboctahedra that share corners with four equivalent Al(1)Nd4Al8 cuboctahedra, faces with two equivalent Nd(1)Al16 cuboctahedra, faces with two equivalent Al(1)Nd4Al8 cuboctahedra, and faces with four equivalent Al(2)Nd4Al8 cuboctahedra. In the second Nd site, Nd(2) is bonded in a 12-coordinate geometry to two equivalent Al(1), two equivalent Al(2), four equivalent Al(3), and six equivalent Al(4) atoms. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded to four equivalent Nd(2), four equivalent Al(2), and four equivalent Al(4) atoms to form distorted AlNd4Al8 cuboctahedra that share corners with four equivalent Nd(1)Al16 cuboctahedra, faces with two equivalent Nd(1)Al16 cuboctahedra, faces with two equivalent Al(1)Nd4Al8 cuboctahedra, and faces with four equivalent Al(2)Nd4Al8 cuboctahedra. In the second Al site, Al(2) is bonded to two equivalent Nd(1), two equivalent Nd(2), two equivalent Al(1), two equivalent Al(3), and four equivalent Al(4) atoms to form distorted AlNd4Al8 cuboctahedra that share corners with four equivalent Al(2)Nd4Al8 cuboctahedra,  an edgeedge with one Al(2)Nd4Al8 cuboctahedra, faces with two equivalent Nd(1)Al16 cuboctahedra, faces with two equivalent Al(1)Nd4Al8 cuboctahedra, and faces with three equivalent Al(2)Nd4Al8 cuboctahedra. In the third Al site, Al(3) is bonded in a 9-coordinate geometry to two equivalent Nd(1), two equivalent Nd(2), one Al(2), one Al(3), and three equivalent Al(4) atoms. In the fourth Al site, Al(4) is bonded in a 10-coordinate geometry to one Nd(1), three equivalent Nd(2), one Al(1), two equivalent Al(2), and three equivalent Al(3) atoms.
Al11Nd3 crystallizes in the orthorhombic Immm space group. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded to four equivalent Al(2), four equivalent Al(4), and eight equivalent Al(3) atoms to form distorted NdAl16 cuboctahedra that share corners with four equivalent Al(1)Nd4Al8 cuboctahedra, faces with two equivalent Nd(1)Al16 cuboctahedra, faces with two equivalent Al(1)Nd4Al8 cuboctahedra, and faces with four equivalent Al(2)Nd4Al8 cuboctahedra. All Nd(1)-Al(2) bond lengths are 3.58 Å. All Nd(1)-Al(4) bond lengths are 3.26 Å. All Nd(1)-Al(3) bond lengths are 3.33 Å. In the second Nd site, Nd(2) is bonded in a 12-coordinate geometry to two equivalent Al(1), two equivalent Al(2), four equivalent Al(3), and six equivalent Al(4) atoms. Both Nd(2)-Al(1) bond lengths are 3.22 Å. Both Nd(2)-Al(2) bond lengths are 3.20 Å. All Nd(2)-Al(3) bond lengths are 3.21 Å. There are four shorter (3.19 Å) and two longer (3.61 Å) Nd(2)-Al(4) bond lengths. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded to four equivalent Nd(2), four equivalent Al(2), and four equivalent Al(4) atoms to form distorted AlNd4Al8 cuboctahedra that share corners with four equivalent Nd(1)Al16 cuboctahedra, faces with two equivalent Nd(1)Al16 cuboctahedra, faces with two equivalent Al(1)Nd4Al8 cuboctahedra, and faces with four equivalent Al(2)Nd4Al8 cuboctahedra. All Al(1)-Al(2) bond lengths are 3.06 Å. All Al(1)-Al(4) bond lengths are 2.86 Å. In the second Al site, Al(2) is bonded to two equivalent Nd(1), two equivalent Nd(2), two equivalent Al(1), two equivalent Al(3), and four equivalent Al(4) atoms to form distorted AlNd4Al8 cuboctahedra that share corners with four equivalent Al(2)Nd4Al8 cuboctahedra,  an edgeedge with one Al(2)Nd4Al8 cuboctahedra, faces with two equivalent Nd(1)Al16 cuboctahedra, faces with two equivalent Al(1)Nd4Al8 cuboctahedra, and faces with three equivalent Al(2)Nd4Al8 cuboctahedra. Both Al(2)-Al(3) bond lengths are 2.64 Å. All Al(2)-Al(4) bond lengths are 2.81 Å. In the third Al site, Al(3) is bonded in a 9-coordinate geometry to two equivalent Nd(1), two equivalent Nd(2), one Al(2), one Al(3), and three equivalent Al(4) atoms. The Al(3)-Al(3) bond length is 2.63 Å. There are two shorter (2.63 Å) and one longer (2.73 Å) Al(3)-Al(4) bond length. In the fourth Al site, Al(4) is bonded in a 10-coordinate geometry to one Nd(1), three equivalent Nd(2), one Al(1), two equivalent Al(2), and three equivalent Al(3) atoms.