AbstractBy doping the copper(I)‐halides with foreign halogen‐ions it is achieved that the spin‐lattice relaxation of63Cu is almost exclusively determined by the quadrupole interactions originating from the diffusion of the Cu+‐ions. From the relaxation rates measured up to the transition temperatures from the γ‐ to the β‐phases mean jump frequencies of the Cu+‐ions are derived. On the basis of a vacancy or a non‐collinear interstitialcy mechanism specific conductivities are calculated from these jump frequencies. For CuCl and CuBr they are in good agreement with conductivities measured directly with the same substances. For CuI the same holds true with the conductivity data of Tubandt. A direct interstitial migration of the cation