The H+ + H2 reaction

H-3(+) plays a crucial role in Astrophysics, taking part in the early chemistry responsible for the formation of the stars. It is also one of the most abundant ionic species in hydrogen plasmas. The spectroscopy of the system has been the subject of intensive work in the past. Association processes to form H-3(+) and dissociative recombination with electrons have also been investigated in detail in order to understand the observed abundance of the molecule in the interstellar medium. Besides all these questions, in this work, we review some of the most relevant aspects regarding the dynamics of the H+ + H-2 reaction and its isotopic variants. A discussion on the most commonly found numerical difficulties in the theoretical study of this reactive collision is included.