Complex Reaction
An overall reaction that proceeds through two or more elementary steps.
Unit
Dimensionless
In depth
The balanced overall equation of a complex reaction gives no information about its rate law, because that is dictated by the mechanism. Complex reactions may show fractional or negative orders, and their apparent activation energy is a composite of several individual barriers.
Examples in the real world
The reaction of hydrogen with bromine, which proceeds by a radical chain and shows an order of 3/2 in H₂ and Br₂.