Abstract: In this paper we have studied active center models of N₃ adsorption on α-Fe(lll) plane clusters by the CNDO method. Obtained conclusions are following:(l)The end-on and the side-on complexes activate dinitrogen by coordination through mainly weakening π-bond in the N₂ molecules. (2) For N₂ adsorptions on the Fe₄ clusters, the bomb-laying type activates the triple bond of the N₂ molecules more than the perpendicular-insertion type. (3) For N₂ adsorptions on the Fe₇ clusters, the perpendicular-insertion type activates the triple bond of dinitrogen more than the bomb-laying type. In general, Fe₇ clusters activate triple bond of dinitrogen more than the Fe₄ clusters. (4) When we consider the charges on the adsorpted dinitrogen in all perpendicular-insertion models sn atom N placing far from adsorbent atom Fe is carried more negatively. The H^δ+ attaches the outside Natom favorably, but for all bomb-laying adsorption types this is not true.