This study investigates the effect FeCl 3 on the radiation stability of the ionic liquid, 1-butyl-3-methylimidazolium chloride (BmimCl) over a wide dose range of 0 to 1000 kGy under γ-ray radiation. The ionic liquid species, BmimFeCl 4 , was formed by adding FeCl 3 into BmimCl. The results showed that the presence of FeCl 4 − significantly improved the radiation resistance of BmimCl, wherein the effect was more pronounced at higher FeCl 4 − content. Meanwhile, under irradiation, Fe(II) was generated from Fe(III), which was reduced by solvated electron. In addition, the concentration of Fe(II) increased with low level of absorbed dose, but leveled off at higher doses. Moreover, the radiation yield of the solvated electrons of BmimCl was further estimated at approximately 0.358±0.01 μmol/J in BmimCl-7 mol% FeCl 3 system. radiation, ionic liquid, FeCl 3 , BmimFeCl 4 , solvated electron Citation: