Related bonding interactions

The term agostic is reserved to describe two-electron, three-center bonding interactions between carbon, hydrogen, and a metal. Two-electron three-center bonding is clearly implicated in the complexation of H₂, e.g., in W(CO)₃(PCy₃)₂H₂, which is closely related to the agostic complex shown in the figure. Silane binds to metal centers often via agostic-like, three-centered Si?H-M interactions. Because these interactions