Termolecular Reaction
An elementary step requiring the simultaneous collision of three species.
Formula / equation
rate = k[A][B][C]
Unit
L²/(mol²·s)
In depth
Three-body collisions are so improbable that termolecular steps are rare and always slow. Where they do occur, the third body usually acts only to carry away excess energy and stabilise the product, as in atmospheric recombination reactions.
Examples in the real world
O + O₂ + M → O₃ + M in the stratosphere, where M is any inert third molecule.