THE atomic nuclear spin data obtained from the analysis of fine structures in line spectra show that odd atomic weight atoms have nuclear spins. There are two groups of odd atomic weight atoms, namely, those with odd and those with even atomic charges. The nuclei of the first group contain an odd number of protons and the nuclei of the second group an odd number of neutrons. A significant experimental fact is that all the nuclei in the first group have positive nuclear spins, whilst nuclei of the second group can exhibit either positive or negative spin values.
Landé, Phys. Rev., 44, 1028; 1933.
Schüler, Z. Phys., 88, 323; 1934.