GdMn3 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Gd is bonded to twelve equivalent Mn atoms to form a mixture of distorted face and corner-sharing GdMn12 cuboctahedra. There are six shorter (2.97 Å) and six longer (2.98 Å) Gd–Mn bond lengths. Mn is bonded in a 12-coordinate geometry to four equivalent Gd and six equivalent Mn atoms. There are two shorter (2.45 Å) and four longer (2.60 Å) Mn–Mn bond lengths.