Iodine ($\mathrm{I}$)

Iodine is the chemical element with atomic number 53 and symbol $\mathrm{I}$. It is a halogen. Elemental iodine consists of ${\mathrm{I}}_2$ molecules and forms a dark molecular solid near room temperature. Iodide is the reduced anion ${\mathrm{I}}^{-}$; the different forms can interconvert in redox chemistry and have different spectroscopic behavior.^[ref]

Historical pharmaceutical preparation; its composition and clinical use must be identified by edition. ^[ref]

Historical pharmaceutical preparation; its composition and clinical use must be identified by edition. ^[ref]

Historical pharmaceutical preparation; its composition and clinical use must be identified by edition. ^[ref]

The mineral-rich residue historically obtained by burning collected seaweeds and leached as a source of iodine-bearing salts.

Iodate is the oxyanion $\mathrm{I}{\mathrm{O}}_3^{-}$, with iodine formally in oxidation state +5. It differs from iodide, in which iodine has oxidation state −1.

Reduction can convert iodate into lower-oxidation-state iodine species. Iodate occurs in some natural deposits and industrial feedstocks, connecting iodine extraction with oxidation-reduction chemistry.

The potassium salt of iodate, formed together with potassium iodide in the reaction of iodine with hot potassium hydroxide.

Triiodide is the anion ${\mathrm{I}}_3^{-}$, formed in the equilibrium ${\mathrm{I}}_2+{\mathrm{I}}^{-}\rightleftharpoons {\mathrm{I}}_3^{-}$. Formation of triiodide can increase the amount of iodine accommodated in an aqueous iodide-containing solution.

The total dissolved iodine inventory therefore need not equal the concentration of free molecular iodine. Interpreting an optical or titration measurement requires the relevant species balance.