Within the typographical limitations of this program, the structural formula for the smallest carboxylate anion, formate, could be written as H-C=O

|

O-1, where the two line unit

|

O-1

should be positioned directly beneath the C in the unit H-C=O.

the ortho isomer is more acidic because the carboxylate anion (the conjugate base) can be stabilized through hydrogen-bonding.

A soapy compound has an anion with one water soluble end, usually a negatively charged carboxylate group, and one fat soluble end, usually made up of carbon and hydrogen.

polyatomic anion

Phosphate is a triply charged polyatomic anion.