NaX zeolite shows a solid state phase transition at a T(c) of 450 K, which undergoes a shift to 470 K upon exchange to NH4X zeolite. The exchange also induces a broadening in the C(p) band and a reduction in the C(p) (at T(c)), DELTAH and E# values. These opposing effects of increased cation mobility (exchange-induced lower C(p) DELTAH and E#) and lattice association (exchange-induced higher T(c) and C(p) band width) are emphasized further when investigating the hysteresis effect of gamma-irradiation on the thermodynamics of the more mobile NH4X transitions. In contrast with gamma-radiation-insensitive NaX, the thermodynamics of the NH4X zeolite solid phase transition at 470 K and the NH4 cation decomposition at 548 K undergo parabolic shifts of transition T(c), C(p) and DELTAH values, which are highly discriminated at 10 Mrad. Below this dose, the gamma-rays induce a consistent drop in the C(p) and DELTAH values, a consistent rise in E#, and an inconsistent rise in the T(c) of the NH4, cation decomposition, and an inconsistent fall in the T(c) of the zeolite lattice transition. All these shifts revert to normal at higher doses causing the hysteresis effect. Strong evidence indicates that gamma-rays induce cation trapping and, therefore, also lattice defects because cation mobility is enhanced; both effects are considered to cause both the mutually opposing thermodynamics and the hysteresis effect observed following the irradiation.