GdNi2Al3 crystallizes in the hexagonal P6/mmm space group. There are two inequivalent Gd sites. In the first Gd site, Gd(1) is bonded in a 18-coordinate geometry to six equivalent Ni(1), six equivalent Al(1), and six equivalent Al(2) atoms. In the second Gd site, Gd(2) is bonded in a hexagonal planar geometry to six equivalent Ni(1) atoms. Ni(1) is bonded in a 9-coordinate geometry to one Gd(2), two equivalent Gd(1), two equivalent Al(1), and four equivalent Al(2) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to four equivalent Gd(1) and four equivalent Ni(1) atoms to form a mixture of distorted face, corner, and edge-sharing AlGd4Ni4 cuboctahedra. In the second Al site, Al(2) is bonded in a 4-coordinate geometry to two equivalent Gd(1) and four equivalent Ni(1) atoms.
GdNi2Al3 crystallizes in the hexagonal P6/mmm space group. There are two inequivalent Gd sites. In the first Gd site, Gd(1) is bonded in a 18-coordinate geometry to six equivalent Ni(1), six equivalent Al(1), and six equivalent Al(2) atoms. All Gd(1)-Ni(1) bond lengths are 3.13 Å. All Gd(1)-Al(1) bond lengths are 3.30 Å. All Gd(1)-Al(2) bond lengths are 3.18 Å. In the second Gd site, Gd(2) is bonded in a hexagonal planar geometry to six equivalent Ni(1) atoms. All Gd(2)-Ni(1) bond lengths are 2.82 Å. Ni(1) is bonded in a 9-coordinate geometry to one Gd(2), two equivalent Gd(1), two equivalent Al(1), and four equivalent Al(2) atoms. Both Ni(1)-Al(1) bond lengths are 2.50 Å. All Ni(1)-Al(2) bond lengths are 2.48 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to four equivalent Gd(1) and four equivalent Ni(1) atoms to form a mixture of distorted face, corner, and edge-sharing AlGd4Ni4 cuboctahedra. In the second Al site, Al(2) is bonded in a 4-coordinate geometry to two equivalent Gd(1) and four equivalent Ni(1) atoms.