[en] Neutron diffraction and magnetometric data show that hexagonal (Li Ga Ge-type crystal structure) R Au Sn compounds (R = Pr, Nd, Gd, Tb, Dy, Ho) order anti ferromagnetically at low temperatures. Their magnetic structures are described by the wavevector k=[1/2, 0, 0]; the magnetic moments are normal to the hexagonal axis in Tb Au Sn and Dy Au Sn, parallel to it in Pr Au Sn and Ho Au Sn and make an angle of 30 deg. in Nd Au Sn. Er Au Sn is cubic (space group F4-bar3m). At T = 1.6 K only a broad peak corresponding to short-range ordering is observed. The observed Neel points range from 2.8 K in Pr Au Sn to 24 K in Gs Au Sn. In all title compounds the magnitudes of ordered magnetic moments at 1.6 K derived from neutron diffraction experiments are smaller than the respective free R³⁺ ion values, indicating a strong effect of the crystalline electric field. (author)