The 23.8-keV Mössbauer resonance of 119Sn and susceptibility measurements have been used to study the structural and magnetic properties of CeSn3, PrSn3, and NdSn3 intermetallic compounds between 293° and 1.6°K. The deterioration of the powder samples, which yields free tin and has led to inconsistent results in the past, is clearly demonstrated in these spectra. Both PrSn3 and NdSn3 exhibit magnetic hyperfine (hf) spectra below their Néel temperatures of 8.6° and 4.7°K, respectively. In PrSn3 one-third of the Sn nuclei experience a transferred hf field of 67 kOe with the spin direction parallel to the principal electric-field-gradient axis while the remaining Sn nuclei display no magnetic splitting. This is interpreted as the result of antiferromagnetic ordering of the first kind. In NdSn3 the magnetic ordering appears to be more complex. In CeSn3 neither magnetic ordering nor the "incipient ferromagnetism" previously suggested is seen. The size of the quadrupole interaction and the isomer shift are nearly equal in all these compounds. © 1970 The American Institute of Physics.