GAMMA-RAY INDUCED DECOMPOSITION OF DOUBLE NITRATES OF LANTHANIDES WITH UNIVALENT AND DIVALENT-CATIONS

Double nitrates of Na and K having the composition 2M(I)NO3 . Ln(III)(NO3)3 . 2H2O(Ln(III) = Pr, Nd, Sm, Eu, Gd, Th and Dy) and of Ni and Cu with the composition 3M(II)(NO3)2.2Ln(III)(NO3)3.24H2O (Ln(III) - La, Ce, Pr, Nd, Sm, Eu, Gd, Th and Dy) have been prepared and their gamma-radiolytic decomposition studied up to 500 kGy. G(NO2-) values o f K double nitrates at 230 kGy follow the order Dy3+ > Pr3+ congruent-to Nd3+ congruent-to Sm3+ > Tb3+ > Eu3+ > Gd3+. G(NO-2) for Ni double nitrates are higher than those of Cu double nitrates. Variation of G(NO2-) with cationic radii and the number of 'f' electrons in lanthanide ion show a minimum at Eu. Thermal decomposition studies of double nitrates were also carried out.