The production of H-2 has been examined in the gamma-ray and 5 MeV He ion radiolysis of CaCl(2)(.)2H(2)O, CaCl2. 6H(2)O, Ca(OH)(2), MgCl(2)(.)2H(2)0, MgCl2-6H2O, and Mg(OH)(2)O. The highest yield for the formation of H-2 is observed in the gamma-radiolysis Of MgCl(2)(.)2H(2)O (0.72 molecule/(100 eV), 75 nmol/J), but the yield decreases with dose due to the relative instability of the dihydrate. The H-2 yields with the other compounds range from 0.04 to 0.2 molecule/(100 eV) (4.2-21 nmol/J), which is lower than that from pure water or 2 M chloride solutions. There appears to be no relationship between the results for H-2 from waters of hydration with that from aqueous salt brines. No particular trend is observed in the radiation chemical yields of H-2 with respect to the cation or the degree of hydration. The production Of Cl-2 is found only in the gamma-radiolysis of CaCl2 with a few weight percent of excess water. No Cl-2 was found in the 5 MeV He ion radiolysis of identical systems. None of the other compounds examined here showed detectable amounts Of Cl-2 formation.