2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/84179The dark Universe corresponds to the period between the thermal decoupling matter-radiation and the formation of the first objects. During this epoq, molecules can appeared. In this talk, I will recall the nucleosynthesis processes, then the chemistry of the primordial Universe. I will discuss the influence of the primordial molecules on the protocloud evolution .Text in french, Talk given at the Ecole Nationale Superieure des Telecommunications -Paris, June 11th 2001; 5 pagesPopular Physicstext