A halide ion is a halogen atom bearing a negative charge. The halide anions are fluoride (F−), chloride (Cl−), bromide (Br−), iodide (I−) and astatide (At−). Such ions are present in all ionic halide salts.
Dihalides are commonly used in the synthesis of cyclic alkanes.
Halide compounds such as KCl, KBr and KI can be tested with silver nitrate solution, AgNO3. The halogen will react with Ag+ and form a precipitate, with colour as follow:
AgF - Yellowish Brown
AgCl - White
AgBr - Creamy (Pale Yellow)
AgI - Yellow
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.
HID (High-intensity discharge) lamps however, contribute highly to light pollution. Sodium-vapor are favored for this reason.
NEC changes affect metal halide lamps: code changes are aimed at preventing risk when metal halide lamps are used in open luminaires and luminaires used in sporting facilities.(METAL HALIDE LAMPS)
Jun 01, 2005; The 2005 Edition of the National Electrical Code (NEC) included two changes that directly affect the manufacture and installation...