Aquation is the
chemical reaction
A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the pos ...
involving "incorporation of one or more integral molecules of water" with or without displacement of other atoms or groups. The term is typically employed to refer to reactions of metal complexes where an anion is displaced by water. For example,
bromopentaamminecobalt(III) undergoes the following aquation reaction to give a
metal aquo complex
In chemistry, metal aquo complexes are coordination compounds containing metal ions with only water as a ligand. These complexes are the predominant species in aqueous solutions of many metal salts, such as metal nitrates, sulfates, and perchlorat ...
:
[{{Greenwood&Earnshaw2nd]
:
o(NH3)5Brsup>2+ + H
2O →
o(NH3)5(H2O)sup>3+ + Br
−
This aquation reaction is catalyzed both by acid and by base.
Acid catalysis
In acid catalysis and base catalysis, a chemical reaction is catalyzed by an acid or a base. By Brønsted–Lowry acid–base theory, the acid is the proton (hydrogen ion, H+) donor and the base is the proton acceptor. Typical reactions catalyzed ...
involves protonation of the bromide, converting it to a better leaving group. Base hydrolysis proceeds by the
Sn1CB mechanism, which begins with deprotonation of an
ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...
ligand.
References
Substitution reactions
Coordination chemistry
Reaction mechanisms
Water chemistry