ErNi3Al9 crystallizes in the trigonal R32 space group. Er(1) is bonded in a 17-coordinate geometry to six equivalent Ni(1), one Al(2), one Al(5), three equivalent Al(3), and six equivalent Al(1) atoms. Ni(1) is bonded in a 8-coordinate geometry to two equivalent Er(1), one Al(2), one Al(3), one Al(4), one Al(5), one Al(6), and three equivalent Al(1) atoms. There are six inequivalent Al sites. In the first Al site, Al(1) is bonded in a 3-coordinate geometry to two equivalent Er(1), three equivalent Ni(1), one Al(2), one Al(4), one Al(5), and two equivalent Al(3) atoms. In the second Al site, Al(2) is bonded in a distorted trigonal non-coplanar geometry to one Er(1), three equivalent Ni(1), one Al(2), three equivalent Al(1), and three equivalent Al(6) atoms. In the third Al site, Al(3) is bonded in a 10-coordinate geometry to two equivalent Er(1), two equivalent Ni(1), two equivalent Al(3), and four equivalent Al(1) atoms. In the fourth Al site, Al(4) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Ni(1), one Al(5), three equivalent Al(1), and three equivalent Al(6) atoms. In the fifth Al site, Al(5) is bonded in a distorted trigonal non-coplanar geometry to one Er(1), three equivalent Ni(1), one Al(4), three equivalent Al(1), and three equivalent Al(6) atoms. In the sixth Al site, Al(6) is bonded in a linear geometry to two equivalent Ni(1), two equivalent Al(2), two equivalent Al(4), and two equivalent Al(5) atoms.
ErNi3Al9 crystallizes in the trigonal R32 space group. Er(1) is bonded in a 17-coordinate geometry to six equivalent Ni(1), one Al(2), one Al(5), three equivalent Al(3), and six equivalent Al(1) atoms. There are three shorter (3.25 Å) and three longer (3.26 Å) Er(1)-Ni(1) bond lengths. The Er(1)-Al(2) bond length is 3.11 Å. The Er(1)-Al(5) bond length is 3.11 Å. All Er(1)-Al(3) bond lengths are 2.96 Å. All Er(1)-Al(1) bond lengths are 3.03 Å. Ni(1) is bonded in a 8-coordinate geometry to two equivalent Er(1), one Al(2), one Al(3), one Al(4), one Al(5), one Al(6), and three equivalent Al(1) atoms. The Ni(1)-Al(2) bond length is 2.54 Å. The Ni(1)-Al(3) bond length is 2.41 Å. The Ni(1)-Al(4) bond length is 2.60 Å. The Ni(1)-Al(5) bond length is 2.55 Å. The Ni(1)-Al(6) bond length is 2.31 Å. There is one shorter (2.42 Å) and two longer (2.45 Å) Ni(1)-Al(1) bond lengths. There are six inequivalent Al sites. In the first Al site, Al(1) is bonded in a 3-coordinate geometry to two equivalent Er(1), three equivalent Ni(1), one Al(2), one Al(4), one Al(5), and two equivalent Al(3) atoms. The Al(1)-Al(2) bond length is 2.74 Å. The Al(1)-Al(4) bond length is 2.69 Å. The Al(1)-Al(5) bond length is 2.75 Å. Both Al(1)-Al(3) bond lengths are 2.77 Å. In the second Al site, Al(2) is bonded in a distorted trigonal non-coplanar geometry to one Er(1), three equivalent Ni(1), one Al(2), three equivalent Al(1), and three equivalent Al(6) atoms. The Al(2)-Al(2) bond length is 2.83 Å. All Al(2)-Al(6) bond lengths are 2.80 Å. In the third Al site, Al(3) is bonded in a 10-coordinate geometry to two equivalent Er(1), two equivalent Ni(1), two equivalent Al(3), and four equivalent Al(1) atoms. Both Al(3)-Al(3) bond lengths are 2.62 Å. In the fourth Al site, Al(4) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Ni(1), one Al(5), three equivalent Al(1), and three equivalent Al(6) atoms. The Al(4)-Al(5) bond length is 2.87 Å. All Al(4)-Al(6) bond lengths are 2.82 Å. In the fifth Al site, Al(5) is bonded in a distorted trigonal non-coplanar geometry to one Er(1), three equivalent Ni(1), one Al(4), three equivalent Al(1), and three equivalent Al(6) atoms. All Al(5)-Al(6) bond lengths are 2.79 Å. In the sixth Al site, Al(6) is bonded in a linear geometry to two equivalent Ni(1), two equivalent Al(2), two equivalent Al(4), and two equivalent Al(5) atoms.