[en] Early actinides (U, Np, Pu, Am) show a particular linear bond actinyl-type structure in their highest oxidation state. The multiple-bond nature of this chemical pattern contributes to a drastic diminution of the charge on the metallic core inducing a strong stabilization of these high oxidation states. The potential participation of the early actinide 5f orbitals in the valence molecular shell is supposed to be one of the most important engines of this chemical specificity. In order to progress in the comprehension of this behavior, a study of the electronic and the geometric structures of some actinyl complexes with different electronic configurations is undertaken using theoretical and experimental approaches. (authors)