Sulfonate

A sulfonic-acid-derived anion or group, with negative charge delocalized over oxygen atoms. Carbon–oxygen substitution of an alkyl sulfonate differs from attack at sulfur.

The salt ${\mathrm{Na}}^{+}[{\mathrm{O}}_3\mathrm{S}(\mathrm{C}{\mathrm{H}}_2{)}_4\mathrm{OC}{\mathrm{H}}_2\mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{H}}_3{]}^{-}$, a product of n-propoxide ring opening of a four-carbon sultone. The ether is at the former oxygen-bound terminal ring carbon.