Carboxylate

A carboxylate anion is an ion with negative chargethat contains the group -COO. It is the conjugate base of a carboxylic acid.

Carboxylic acids dissociate into a carboxylate ion and a positively-charged hydrogen ion (proton) much more readily than alcohols dissociate (into an alkoxide ion and a proton), because the carboxylate ion is more stable: the negative charge that is left behind when a proton leaves the carboxylate group is 'shared' between the two electronegative oxygen atoms in a resonance structure. This delocalization of the electron cloud means that neither of the oxygen atoms is so strongly negatively charged; the positively-charged proton is therefore less readily attracted back to the carboxylate group once it has left. On the other hand, 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. Thus, the carboxylate ion is more stable - this is also why carboxylic acids have a lower pH than alcohols: the higher the number of protons that escape into solution, the lower the pH. [cite book | author= Fox, Marye Anne; Whitesell, James K. | year = 1997 | title = Organic Chemistry | edition = 2| publisher = Jones and Bartlett Publishers | location = Sudbury, Massachusetts| id = ISBN 0-7637-0178-5 ]

Examples

* formate ion, HCOO
* acetate ion, CH3COO

Discussion

References


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Look at other dictionaries:

  • carboxylate — car*box yl*ate v. t. to treat a chemical compound with carboxyl or carboxylic acid. [WordNet 1.5] …   The Collaborative International Dictionary of English

  • carboxylate — ● carboxylate nom masculin Sel ou ester d un acide carboxylique …   Encyclopédie Universelle

  • carboxylate — [kär bäks′ə lāt΄] n. a salt or ester of a carboxylic acid vt. carboxylated, carboxylating to form a carboxylic acid by introducing a carboxyl group into (a compound) carboxylation n …   English World dictionary

  • Carboxylate — Acide carboxylique Modèle éclaté d un groupement carboxyle. Le terme acide carboxylique désigne une molécule comprenant un groupement carboxyle. Ce sont des acides et leurs bases conjuguées sont appelées carboxylates. En chimie organique, un… …   Wikipédia en Français

  • carboxylate — n. salt from carboxylic acid (Chemistry) v. add carboxylate (chemical substance) to a compound …   English contemporary dictionary

  • carboxylate — karboksilatas statusas T sritis chemija formulė RCOO(M,R) atitikmenys: angl. carboxylate rus. карбоксилат …   Chemijos terminų aiškinamasis žodynas

  • carboxylate — I. noun Date: 1884 a salt or ester of a carboxylic acid II. transitive verb ( ated; ating) Date: 1921 to introduce carboxyl or carbon dioxide into (a compound) with formation of a carboxylic acid • carboxylation noun …   New Collegiate Dictionary

  • carboxylate — /kahr bok seuh layt /, v., carboxylated, carboxylating, n. v.t. 1. to introduce the carboxyl group into (an organic compound). n. 2. a salt or ester of a carboxylic acid. [1925 30; CARBOXYL + ATE2] * * * …   Universalium

  • carboxylate — noun Any salt or ester of a carboxylic acid …   Wiktionary

  • carboxylate — car·box·yl·ate .lāt vt, at·ed; at·ing to introduce carboxyl or carbon dioxide into (a compound) with formation of a carboxylic acid car·box·yl·ation (.)kär .bäk sə lā shən n car·box·yl·ate .lāt, lət n a salt or ester of a carboxylic acid * * *… …   Medical dictionary


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