What is "hydrogen iodide"

Hydriodic \Hy`dri*od"ic\, a. [Hydr- + iodic: cf. F. hydriodique.] (Chem.) Pertaining to, or derived from, hydrogen and iodine; -- said of an acid ( HI) produced by the combination of these elements.

Hydriodic acid (Chem.), a pungent, colorless gas, HI, usually prepared as a solution in water. It is strong reducing agent. Called also hydrogen iodide.

n. (context inorganic compound English) a colourless gas with molecular formula HI, having a suffocating smell; it forms hydriodic acid when dissolved in water

n. a colorless gas that yields hydroiodic acid in aqueous solution

Hydrogen iodide is a diatomic molecule and hydrogen halide. Aqueous solutions of HI are known as hydroiodic acid or hydriodic acid, a strong acid. Hydrogen iodide and hydroiodic acid are, however, different in that the former is a gas under standard conditions, whereas the other is an aqueous solution of said gas. They are interconvertible. HI is used in organic and inorganic synthesis as one of the primary sources of iodine and as a reducing agent.

This page provides supplementary chemical data on hydrogen iodide.