The condensation of Fe atoms was studied over the temperature range of 670-1150 K at pressures between 0.3 and 0.45 bar behind incident shock waves based on Fe concentration measurements. Atomic resonance absorption spectroscopy was applied to follow Fe atoms in gas mixtures containing Fe(CO)(5) as iron precursor, highly diluted in argon. At the upper experimental temperature limit, the experiments showed constant Fe-atom concentration levels after decomposition of the precursor. At a lower temperature, a time dependent decrease of the Fe concentration was observed showing an inverse temperature dependency. A simplified reaction mechanism consisting of a one step decomposition of the precursor and various iron consumption reactions was proposed for the simulation of the signals. The major initial reactions for the understanding of the condensation process were found to be the formation and the decomposition of Fe-2 (see reactions R2 and R3 in the text). The rate coefficients of both reactions were determined experimentally to be k(2) = 10(19) cm(6) mol(-2) s(-1) and k(3) = 10(19.63+/-0.40) exp(-17800 +/- 700 K/T) cm(3) mol(-1) s(-1) (for reactions R2 and R3, respectively).