Studies performed on proponium cations at the ab initio level show that six different stable structures can be characterized: four proponium cations and two van der Waals complexes. Among the proponium cations, the most stable structure corresponds to the C-proponium ion. Between the van der Waals complexes, the most stable one corresponds to the structure that results from the interaction between the isopropyl ion and the hydrogen molecule. The topology of the electronic density charge of the different structures is studied, at ab initio level, using the theory of atoms in molecules (AIM) developed by Bader.