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A carboxylate is a salt or ester of a carboxylic acid. ''Carboxylate salts'' have the general formula M(RCOO)''n'', where M is a metal and ''n'' is 1,2,...; ''carboxylate esters'' have the general formula RCOOR'. R and R' are organic groups; R'≠H. A carboxylate ion is the conjugate base of a carboxylic acid, RCOO−. It is an ion with negative charge. == Resonance stabilization of the carboxylate ion== Carboxylic acids easily dissociate into a carboxylate anion and a positively charged hydrogen ion (proton), much more readily than alcohols do (into an alkoxide ion and a proton), because the carboxylate ion is stabilized by resonance. The negative charge that is left after deprotonation of the carboxyl group is delocalized between the two electronegative oxygen atoms in a resonance structure. : This delocalization of the electron cloud means that both of the oxygen atoms are less strongly negatively charged; the positive proton is therefore less strongly attracted back to the carboxylate group once it has left; the carboxylate ion is more stable . In contrast, an alkoxide ion, once formed, would have a strong negative charge on the oxygen atom, which would make it difficult for the proton to escape. Carboxylic acids have a lower pH than alcohols: the higher the number of protons in solution, the lower the pH. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Carboxylate」の詳細全文を読む スポンサード リンク
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