Résumé
We present results of measurements of dielectric spectroscopy concerning the 4kF charge density wave associated with the charge ordering (CO) of Wigner type in (TMTTF)2X conductors. This CO transition is due to cor- related electron interactions on the molecular chains and to the appropriate displacement of the anion chains (transition at q = 0). Recent experiments on the substitution of hydrogen by deuterium in TMTTF molecules will be reported. In the vicinity of Tco it has also been found the divergence of the relaxation time and the development of a low frequency shoulder in the fre- quency dependence of the imaginary part of the dielectric permittivity, which are typical features for classical ferroelectrics.