Halide

Binary compounds of halogens with less electronegative elements.

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A halide (rarely halogenide) is a binary chemical compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative (or more electropositive) than the halogen, to make a fluoride, chloride, bromide, iodide, astatide, or theoretically tennesside compound.

Last updated 2026-10-03 from the source article.

Quick Facts

Field: Chemistry
Known for: Binary compounds with halogens; used in metal halide lamps, photographic films, and soldering flux

Facts from the source article.

Lore & Background

Alkali metals and halogens react to form halides with the formula MX, where X is fluorine, chlorine, bromine, or iodine. Many salts and minerals are halides, which also form covalent compounds like titanium tetrafluoride, titanium tetrachloride, titanium tetrabromide, and titanium tetraiodide. The heavier titanium tetrachloride, tetrabromide, and tetraiodide are molecular and can be distilled easily, but titanium tetrafluoride has a polymeric structure and a melting point of 284 degrees Celsius. Fluorides generally behave differently from the heavier halides.

Reader's Guide

Halides cannot be reduced under the usual laboratory conditions, but they all can be oxidized to the parent halogens, which are diatomic. Especially for iodide and less so for the lighter halides, intermediates can be observed and isolated. Best characterized is triiodide. Many related species are known, including a host of polyiodides. Halides are conjugate bases of hydrogen halides, which are all gases. When the protonation is conducted in aqueous solution, hydrohalic acids are produced. Halide salts such as (not specified in source) are highly soluble in water to give colorless solutions. The solutions react readily with a solution of silver nitrate. These three halides form solid precipitates: white, pale yellow, yellow. Similar but slower reactions occur with alkyl halides in place of alkali metal halides, as described in the Beilstein test.

Did You Know?

All common halide anions (fluoride, chloride, bromide, iodide) are colorless.
TiF4 is a white solid, not colorless.
Silver halides are used in photographic films and papers.
Metal halides are used in high-intensity discharge lamps called metal halide lamps.