“…Although these studies generally show a reduction of iron(III) into iron(II), the nature of the iron(II) species has been reported to be dependent on both alkali nature (M) and hydration number (x) of the initial ferric complex. For heavy alkali (M=K,Cs), the ferrous products have been identified as a double oxalate of iron and the corresponding alkali, M 2 Fe(C 2 O 4 ) 2Iy H 2 O, with an hydration number y depending on the water content of the initial ferric compound [1][2][3][4] and, in some cases, on the irradiation conditions [5,6]. However, as already shown in a previous study [7] on Li 4 Fe(C 2 O 4 ) 3 .Cl.9H 2 O, for light alkali, the only ferrous radiolytic product was found to be FeC 2 O 4 .2H 2 O.…”