Phosphirane is the organophosphorus compound with the formula C2H4PH. It is a colorless gas of no commercial value. As the simplest cyclic, saturated organophosphorus compound, phosphirane is the prototype of a family of related compounds that have attracted attention from the research community. Phosphirane was first prepared by reaction of 1,2-dichloroethane with the conjugate base of phosphine.[1] Phosphiranes, that is substituted phosphirene compounds where one or more of the H's are replaced organic substituents, are far more commonly discussed than the parent phosphirane.