EPR Study of Impurity—Vacancy Aggregates in NaCl Containing Both Mn2+ and Other Divalent Cations

Several aggregation products involving divalent cation—cation vacancy complexes in NaCl have been studied using the EPR of Mn2+ which is present as a minor constituent. As the probability that the aggregation product contains more than a single Mn2+ is small, the EPR spectrum of the Mn2+ should be indicative of the symmetry of the aggregates. The principal axes of aggregates produced by an anneal were detected with EPR and compared with those calculated for possible models. Three spectra newly found were identified tentatively as a dimer with 〈100〉 symmetry, large aggregates probably in {111} planes, and a Mn2+ occupying a cubic site in a second‐phase precipitate.