Formate

Formate (also known as methanoate) is a salt or ester of formic acid. It is also an ion of formic acid. It is formed when formic acid dissolves in water (which splits into a formate anion and a hydron). The chemical formula is HCOO- (also written as HCO2-) as an ion itself. Formate salts and esters are usually colourless.

Formate esters
Formate esters have the chemical formula HCOOR (where R is an organic group like an alkyl or aryl group). It is made when formic acid reacts with an alcohol to make a formate ester and water.

The reaction between formic acid and ethanol gives ethyl formate and water:

HCOOH + CH3OH ⇌  + H2O

Formate salts
Formate salts are made when formic acid reacts with a base (like sodium hydroxide).

The reaction between formic acid and sodium hydroxide gives sodium formate and water:

HCOOH + NaOH —> HCOONa + H2O

Examples
Methyl formate: HCOOCH3
Ethyl formate: HCOOC2H5
Sodium formate: HCOONa
Potassium formate: HCOOK

Related pages
Acetate
Carboxylate
Carboxylic acid

Category:Carboxylate anions