A halide is a binary phase, o which ane pairt is a halogen atom an the ither pairt is an element or radical that is less electronegative (or mair electropositive) than the halogen, tae mak a fluoride, chloride, bromide, iodide, astatide, or theoretically tennesside compound. The alkali metals combine directly wi halogens unner appropriate conditions forming halides o the general formula, MX (X = F, Cl, Br or I). Mony salts are halides; the hal- syllable in halide an halite reflects this correlation. Aw Group 7 metals form halides that are white solids at room temperature.
A halide ion is a halogen atom bearing a negative charge. The halide anions are fluoride (F−), chloride (Cl−), bromide (Br−), iodide (I−) an astatide (At−). Sic ions are present in aw ionic halide salts. Halide minerals contain halides.
Aw thir halides are colourless, heich melting crystalline solids haein heich negative enthalpies o formation.
- AgF: no precipitate
- AgCl: white
- AgBr: creamy (pale yellae)
- AgI: green (yellow)
Uses[eedit | eedit soorce]
Metal halides are uised in heich-intensity discharge lamps cried metal halide lamps, sic as those uised in modren street lichts. Thir are mair energy-efficient than mercury-vapor lamps, an hae much better colour rendition than orange heich-pressure sodium lamps. Metal halide lamps are an aa commonly uised in greenhouses or in rainy climates tae supplement naitural sunlight.
Siller halides are uised in photographic films an papers. When the film is developed, the siller halides which hae been exposed tae licht are reduced tae metallic siller, forming an image.
Halides are an aa uised in solder paste, commonly as a Cl or Br equivalent.
Synthetic organic chemistry eften incorporates halogens intae organohalide compounds.
Compounds[eedit | eedit soorce]
Examples o halide compounds are:
- Sodium chloride (NaCl)
- Potassium chloride (KCl)
- Potassium iodide (KI)
- Lithium chloride (LiCl)
- Copper(II) chloride (CuCl2)
- Siller chloride (AgCl)
- Calcium chloride (CaCl2)
- Chlorine fluoride (ClF)
- Bromomethane (CH3Br)
- Iodoform (CHI3)
- Hydrogen chloride (HCl)