The primary reaction of titanium-catalyzed oligomerization of phosphorus using methylphosphine as a reagent has been studied with a highly accurate quantum mechanical procedure. The reaction proceeds as a two-step process with the titanium atom catalyzing the migration of a hydrogen atom from carbon to phosphorus by delocalizing electrons into its unoccupied d orbitals. Thus in the transition state of the second step it has been clearly identified a two-electron three-center bond among titanium, the phosphorus, and the migrating hydrogen atom, which drives the hydrogen from the carbon over to the phosphorus.