Halide

Redox 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. Protonation Halides are conjugate bases of hydrogen halides, which are all gases. When the protonation is conducted in aqueous solution, hydrohalic acids are produced. Reaction with silver ions Halide salts such as Potassium chloride|, Potassium bromide| and Potassium iodide| 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: • Silver chloride|: white • Silver bromide|: pale yellow • Silver iodide|: yellow Similar but slower reactions occur with alkyl halides in place of alkali metal halides, as described in the Beilstein test. ==Uses==

Metal halides are used in high-intensity discharge lamps called metal halide lamps, such as those used in modern street lights. These are more energy-efficient than mercury-vapor lamps, and have much better colour rendition than orange high-pressure sodium lamps. Metal halide lamps are also commonly used in greenhouses or in rainy climates to supplement natural sunlight. Silver halides are used in photographic films and papers. When the film is developed, the silver halides which have been exposed to light are reduced to metallic silver, forming an image. Halides are also used in soldering flux, commonly as a Cl or Br equivalent (e.g ZnCl). Synthetic organic chemistry often incorporates halogens into organohalide compounds. ==See also==