COOHCOO

COOHCOO is not a standard chemical term, but it can be read as a concatenation of two carboxyl-related fragments: COOH, the carboxyl functional group, and COO-, the carboxylate anion. In informal or schematic notation, COOHCOO may be used to indicate a molecule that contains both a protonated carboxyl group (COOH) and a deprotonated carboxylate group (COO−), or more generally to signal the presence of carboxyl groups within a larger structure.

Possible interpretations vary by context. In solution, carboxyl groups display acid–base behavior: COOH can lose a proton to become COO−, with the deprotonated form typically dominating at higher pH. Compounds containing both forms can resemble zwitterions in certain environments, although COOHCOO as written does not specify a particular molecular arrangement. In salt form, carboxylate groups frequently coordinate with metal cations (for example, sodium acetate is a carboxylate salt), while in organic synthesis carboxyl groups participate in reactions to form esters, anhydrides, or amides.

Nomenclature for a specific molecule containing two carboxyl groups requires a defined carbon skeleton. For example, oxalic acid (ethanedioic acid) has two carboxyl groups on adjacent carbons, while other diacids, such as succinic or adipic acids, place carboxyl groups on longer carbon chains. As a fragment, COOHCOO does not convey a unique compound; its precise meaning depends on the underlying structure and the chemical context in which it appears.

See also: carboxyl group, carboxylate, zwitterion, diacid, esters.