Carboxylate

A carboxylate is the conjugate base of a carboxylic acid, RCOO− (or RCO−2). It is an ion with negative charge. Carboxylate ions are made when a carboxylic acid loses a hydrogen ion. Such acids usually have pKa of less than 5, meaning that many bases, such as sodium hydroxide or sodium bicarbonate can remove the hydrogen ions from them.
RCOOH + NaOH → RCOONa + H2O
Examples.
Some examples of carboxylates include;