Elementary vs Overall Reactions

Elementary reactions are defined as those that cannot be broken down into two or more simpler reactions. Generally, they consist of one or two reactant species and are referred to as unimolecular and bi-molecular processes, respectively. However, there are a 

Examples of these three classes of gas-phase reactions are 

Termolecular. The formation of ozone by the reaction of a ground-state oxygen atom, 0(3P), with 02  

Because M does not enter into the reaction chemically, such reactions are usually written with M above the arrow, although in some cases it is omitted entirely and simply understood to be present  

Each of these types of elementary processes will be treated in some detail in subsequent sections of this chapter. 

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