This paper reports the specific conditions used in the preparation of RCrO oxides, R5Nd, Sm, Eu and Lu, the structural determination, 4 and the study of their magnetic behaviour. The structure of these compounds has been refined from X-ray powder diffraction by the Rietveld method, assigning the zircon type, space group I4 /amd. A linear decrease has been observed in the lattice parameters from ntiferromagnetic ordering in which both Cr and R sublattices are involved. In the case of NdCrO , the estimated Neel temperature 4 appears to be lower than 2 K; for the remaining oxides, it is 14.9 K, 15.9 K and 9.9 K for Sm, Eu and Lu, respectively. A superexchange mechanism has been proposed to explain such a magnetic behaviour. The pathways through which these interactions take place have also 51 been analysed, taking into account the structural features that these oxides present. The Cr plays an important role as a promoter of 31 these interactions in the R sublattice.