Experimental study on (F2+)* centers in NaF:Mg2+ crystals is reported in this paper. A process of type transfer from F2+ to (F26+)* centers was observed in our ex Periment. The rate of transfer depends on the type of doped divalent metal ions rather than the concentration of doped cations. It was also found that the products of thermal bleaching of the(F2+)* centers exhibit the same properties as that of Z4 centers. From the results of experiments we propose a possible model that the (F2+)* center is formed of a F2+ center connected to an I-V pair.