Lithium chloride
Cubic
Li, Cl
- 7447-41-8
- 16712-20-2 (monohydrate)
White solid
Fixed
2.07 g · cm -3
615 ° C
1360 ° C
- Well in water: 832 g · l-1 (20 ° C)
- Soluble in methanol
1,662
Attention
526 mg • kg -1 ( LD50, rat, oral)
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Lithium chloride LiCl, the lithium salt of hydrochloric acid, forms colorless, highly hygroscopic crystals. In addition to the anhydrous lithium chloride are also various hydrates, are known LiCl · H2O n with n = 1, 3 and 5
Properties
Lithium chloride solutions are strongly hygroscopic. They reduce the water vapor pressure by about 90%. From concentrated aqueous solutions of anhydrous lithium chloride crystallizes only triggered at temperatures above 98 ° C. At lower temperatures to obtain a hydrated. The solubility in water is approximately 450 g LiCl / kg solution. Gaseous lithium chloride is lithium chloride planar rings of several molecules ( di-, tri-and oligomers).
Lithium chloride solutions are very corrosive. For handling concentrated solutions suitable materials are to be selected. Lithium chloride solutions also damage concrete.
The standard enthalpy of formation of crystalline lithium chloride is ΔfH0298 = -408.27 kJ / mol.
Representation
The recovery of lithium chloride is carried out by reaction of an aqueous lithium hydroxide or lithium carbonate with hydrogen chloride and subsequent concentration and drying.
Technically relevant is currently only reacting lithium carbonate with hydrochloric acid followed by concentration under crystallization of lithium chloride in vacuum evaporators.
In addition, lithium chloride precipitates common in organometallic syntheses as a by- product ( salt metathesis ).
Use
Lithium chloride can be used for producing lithium. For this purpose, a mixture of lithium chloride and potassium chloride is used in a fused bath electrolysis. Because of the strong hygroscopic effect, it can be used as a drying agent, and also to room dehumidification. Furthermore, it can be used as a flux in soldering and welding technology. Because of its hygroscopic nature, it can be used in dew point sensors or hygrometers. The electrical conductivity of the salt is highly dependent on the water concentration, and therefore the ambient humidity can be determined from the conductivity of the lithium chloride. In chemical or geological studies lithium chloride can be used as a tracer. Lithium chloride may be used in Enteiserlösungen. However, since these are corrosive, they are, for example, prohibited for use on aircraft in the U.S.. The textile industry uses lithium chloride. In cooling baths lithium chloride solutions can come up with 25-30 % LiCl used. Such cold baths can remain liquid down to -70 ° C.