Contribution to the study of fluoride and oxyfluoride elements 4d, 5d and 5f by thermochromatography

The results exposed in this report constitute an extension of works effected in laboratory of Radiochemistry, on the thermochromatography. They confirm the validity of this method as way to identify oxidation states of element. In a first time experimental results realised in fluorined atmosphere on Tc, Re, Os, Mo and Ir by thermochromatography, have enable to extend the identification scope right to seven valency. This results applied to actinides and especially to neptunium and plutonium have given rise to identification for the first time, in gas phase, the next compounds: PuO2F3, PuOF5, NpO3F, NpO2F3, NpOF5, NpF7 and the confirmation to PuO3F. Moreover the adsorption heat of UF4, UF6 and IrOF4 has been determined. The adsorbent surface has been studied by Electron Spectroscopy for Chemical Analysis (E.S.C.A.), it is an homogeneous layer of NiF2 along the thermochromatograph. The valency 6 of the molybdene has been confirmed on the compound identified by thermochromatography as MoOF4. The theoretical model of adsorption founded on a chimisorption process between one fluorined or oxyfluorined Ru molecules and one then two NiF2 molecules, allow to make out lineares correlations between the complex adsorbent-adsorbat energezing gain of formation and the characteristic deposition temperature, significant of the compound and the element valency