Gamma ray induced decomposition of double nitrates of lanthanum and cerium with some mono and bivalent cations in solid state

Gamma ray induced decomposition of two series of double nitrates: 2M1NO3·Ln(NO3)3· xH2O (where M1 NH4+, Na+, K+, Rb+, Cs+; LnIII = La3+, Ce3+ and x = 2 or 4) and 3MII(NO3)2·2LnIII(NO3)3·24H2O (where MII = Mg2+, Co2+, Zn2+; LnIII La3+, Ce3+) has been studied in solid state over a wide absorbed dose range at room temperature. G(NO2-) values have been found to depend on the absorbed dose and the nature of cation in both the series of double salts. Radiation sensitivity of lanthanum double nitrates with monovalent cations at an absorbed dose of 158 kGy follows the order NH4+ < Rb+ approx Cs+ < Na+ < K+ and those of cerium NH4+ < Rb+ < Na+ < K+. G(NO2-) values of lanthanum double nitrates with bivalent cations at an absorbed dose of 206 kGy range from 0.22 to 1.05 and follow the order Zn2+ approx Co2+ < Mg2+ while for cerium salts are in the range 0.62-0.91 in the order Zn2+ approx Co2+ < Mg2+. In fact double nitrates of cerium with Zn2+ and Co2+ exhibit almost similar G(NO2-) values over the dose range 5-640 kGy. X-ray power diffraction patterns of the irradiated Mg-La double salt indicate the possibility of structural phase transformation at certain doses. (author)