What does carboxylate mean?
A carboxylate is a salt or ester of a carboxylic acid — that is, a compound containing the negatively charged group –COO⁻, formed when a carboxylic acid loses its acidic hydrogen. The word also serves as a verb: chemists carboxylate a molecule when they introduce a carboxyl group into it, often by reaction with carbon dioxide. Carboxylates are everywhere in practical life and nature: soaps and detergents are typically sodium or potassium carboxylates of long-chain fatty acids, metal carboxylates act as catalysts and paint driers, and amino acids exist largely as carboxylate anions within living cells. Strictly technical in register, the term belongs to organic chemistry, biochemistry, and pharmacology rather than general conversation, but it names one of the most functionally important groups in all of chemistry — the reactive handle that makes acids acidic and soaps soluble.
A salt or ester of a carboxylic acid, containing the anionic group –COO⁻.
"Calcium carboxylate precipitated out of the solution as a white solid."
In formulas and mechanisms, the carboxylate is usually written as –COO⁻ or RCO₂⁻.
To introduce a carboxyl group into a molecule, or to convert a compound into its carboxylate form.
"The team used a palladium catalyst to carboxylate the aryl bromide directly with carbon dioxide."
Applies only to the noun sense; salts and esters are routinely referred to in the plural when discussing classes of compounds.
"Long-chain fatty acid carboxylates are the active ingredients in ordinary soap."
Every soap you've ever used worked because of a carboxylate — the humble –COO⁻ group is why soap grabs grease in one end and water in the other.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of carboxylate
The term derives from 'carboxyl', the name for the –COOH group, itself a blend coined in the 19th century combining 'carb-' (from Latin carbo, meaning coal or charcoal) with 'oxy-' from oxygen, reflecting the group's composition of carbon, oxygen, and hydrogen. The verb and noun forms developed as chemistry formalised the study of organic acids and their salts during the 1800s. Cognate terms built on the same Latin root carbo include carbonate, carbonic, and carbohydrate.
Related word forms
How carboxylate is actually used
This is a technical term confined almost entirely to chemistry and biochemistry; it is rare in everyday speech. The noun and verb are pronounced identically. In biochemical contexts, 'carboxylate' often refers specifically to the deprotonated, anionic form of a carboxylic acid at physiological pH.
Easily confused with carboxylate
A carbonate is a salt of carbonic acid containing the CO₃²⁻ ion, whereas a carboxylate is derived from an organic carboxylic acid containing the –COO⁻ group.