The fusion reaction

The fusion reaction (or creation, formation reaction) - is a chemical process during which more complex chemical products are formed from simple substrates.

There is no such thing as a general synthesis scheme. All we can do is write out only schemes for certain types of reactions, such as reactions during which only one product is formed from several substrates:

aA + bB + cC + ... → A_aB_bC_c...

where:

A, B, C etc is the substrate
a, b, c, etc are the stoichiometric coefficients
A_aB_bC_c... product created

examples:

2 Mg + O₂ → 2 MgO

2 K + Cl₂ → 2 KCl

S + O₂ → SO2

4 Fe + 3 O₂→ 2 Fe₂0₃

CO₂ +H₂O →H₂CO₃

The inverse of the fusion reaction is the analysis reaction, otherwise known as the decomposition reaction.