Decomposition Reaction
A reaction in which a single compound breaks down into two or more simpler substances.
Formula / equation
AB → A + B
Unit
Dimensionless
In depth
Decomposition is the reverse of combination and almost always endothermic, since bonds must be broken. The energy is supplied as heat, light or electricity, giving the thermal, photochemical and electrolytic subtypes. Many decompositions release a gas, making them useful for gas preparation.
Examples in the real world
2H₂O → 2H₂ + O₂ by electrolysis; silver bromide darkening in light; limestone calcining to lime.