Anion

An anion is an ion with negative net electric charge, for example ${\mathrm{Cl}}^{-}$ or hydroxide.

The singly charged anion of fluorine. Its affinity for silicon makes it useful for cleaving silyl protecting groups.

The anion $\mathrm{N}{\mathrm{H}}_2^{-}$ is the conjugate base of Ammonia. It is chemically distinct from an organic amide functional group and can deprotonate suitable carbon acids.

A sulfuric-acid monoester involved in a traditional account of producing diethyl ether from ethanol.

An ionic compound containing divalent magnesium and sulfate ions. Its nominal formula concentration $c$ contributes ionic strength $4c$ when fully dissociated into these two ion species.

Chloride is the anion $\mathrm{C}{\mathrm{l}}^{-}$, with net electric charge $-e$. In the glycine titration model, it supplies the negative background electric charge introduced with hydrochloric acid.

A manganese-containing anion with net electric charge $-e$ and manganese oxidation state $+7$; $e$ is the positive elementary charge.

The nitrate ion, ${\mathrm{NO}}_3^{-}$, is an anion with one nitrogen connected to three oxygen chemical atoms and net electric charge $-1$ in units of elementary charge. Its 24 valence electrons admit three equivalent octet resonance structures; see Lewis structure for their construction and chemical resonance for their interpretation. The N–O connections are covalent bonds within the ion. See 7.2 Covalent Bonding.

A historical nitrate-recognition reaction involving reduction by iron(II) and formation of a brown iron–nitrosyl species. Nitrite, reagent contamination and procedural conditions can interfere.