Lithium chloride

Lithium chloride

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Names
Preferred IUPAC name Lithium chloride
Systematic IUPAC name Lithium(1+) chloride
Identifiers
CAS Number	7447-41-8 Y
ChEBI	CHEBI:48607 Y
ChEMBL	ChEMBL69710 N
ChemSpider	22449 Y=  N
EC Number	231-212-3
Jmol 3D model	Interactive image
MeSH	Lithium+chloride
PubChem	433294
RTECS number	OJ5950000
UNII	G4962QA067 Y
UN number	2056
InChI InChI=1S/ClH.Li/h1H;/q;+1/p-1 N Key: KWGKDLIKAYFUFQ-UHFFFAOYSA-M N InChI=1S/ClH.Li/h1H;/q;+1/p-1 Key: KWGKDLIKAYFUFQ-UHFFFAOYSA-M InChI=1/ClH.Li/h1H;/q;+1/p-1 Key: KWGKDLIKAYFUFQ-REWHXWOFAB
SMILES [Li+].[Cl-]
Properties
Chemical formula	ClLi
Molar mass	42.39 g·mol−1
Appearance	white solid hygroscopic, sharp
Density	2.068 g/cm3
Melting point	605–614 °C (1,121–1,137 °F; 878–887 K)
Boiling point	1,382 °C (2,520 °F; 1,655 K)
Solubility in water	68.29 g/100 mL (0 °C) 74.48 g/100 mL (10 °C) 84.25 g/100 mL (25 °C) 88.7 g/100 mL (40 °C) 123.44 g/100 mL (100 °C)
Solubility	soluble in hydrazine, methylformamide, butanol, selenium(IV) oxychloride, propanol
Solubility in methanol	45.2 g/100 g (0 °C) 43.8 g/100 g (20 °C) 42.36 g/100 g (25 °C) 44.6 g/100 g (60 °C)
Solubility in ethanol	14.42 g/100 g (0 °C) 24.28 g/100 g (20 °C) 25.1 g/100 g (30 °C) 23.46 g/100 g (60 °C)
Solubility in formic acid	26.6 g/100 g (18 °C) 27.5 g/100 g (25 °C)
Solubility in acetone	1.2 g/100 g (20 °C) 0.83 g/100 g (25 °C) 0.61 g/100 g (50 °C)
Solubility in liquid ammonia	0.54 g/100 g (-34 °C) 3.02 g/100 g (25 °C)
Vapor pressure	1 torr (785 °C) 10 torr (934 °C) 100 torr (1130 °C)
Refractive index (nD)	1.662 (24 °C)
Viscosity	0.87 cP (807 °C)
Structure
Coordination geometry	Octahedral
Molecular shape	Linear (gas)
Dipole moment	7.13 D (gas)
Thermochemistry
Specific heat capacity (C)	48.03 J/mol·K
Std molar entropy (So298)	59.31 J/mol·K
Std enthalpy of formation (ΔfHo298)	-408.27 kJ/mol
Gibbs free energy (ΔfG˚)	-384 kJ/mol
Vapor pressure	{{{value}}}
Related compounds
Other anions	Lithium fluoride Lithium bromide Lithium iodide
Other cations	Sodium chloride Potassium chloride Rubidium chloride Caesium chloride
Supplementary data page
Structure and properties	Refractive index (n), Dielectric constant (εr), etc.
Thermodynamic data	Phase behaviour solid–liquid–gas
Spectral data	UV, IR, NMR, MS
N verify (what is YN ?)
Infobox references

Lithium chloride is a chemical compound with the formula LiCl. The salt is a typical ionic compound, although the small size of the Li⁺ ion gives rise to properties not seen for other alkali metal chlorides, such as extraordinary solubility in polar solvents (83.05 g/100 mL of water at 20 °C) and its hygroscopic properties.

Chemical properties

The salt forms crystalline hydrates, unlike the other alkali metal chlorides. Mono-, tri-, and pentahydrates are known. The anhydrous salt can be regenerated by heating the hydrates. Molten LiCl and LiCl-based mixtures react under a humid atmosphere to form lithium hydroxide and hydrogen chloride. Molten LiCl hydrolyzes to give LiOH and HCl. LiCl also absorbs up to four equivalents of ammonia/mol. As with any other ionic chlorides, solutions of lithium chloride can serve as a source of chloride ion, e.g., forming a precipitate upon treatment with silver nitrate:

LiCl + AgNO₃ → AgCl + LiNO₃

Preparation

Lithium chloride is produced by treatment of lithium carbonate with hydrochloric acid. It can in principle also be generated by the highly exothermic reaction of lithium metal with either chlorine or anhydrous hydrogen chloride gas. Anhydrous LiCl is prepared from the hydrate by heating with a stream of hydrogen chloride.

Uses

Lithium chloride is mainly used for the production of lithium metal by electrolysis of a LiCl/KCl melt at 450 °C (842 °F). LiCl is also used as a brazing flux for aluminium in automobile parts. It is used as a desiccant for drying air streams. In more specialized applications, lithium chloride finds some use in organic synthesis, e.g., as an additive in the Stille reaction. Also, in biochemical applications, it can be used to precipitate RNA from cellular extracts.

Lithium chloride is also used as a flame colorant to produce dark red flames.

Lithium chloride is used as a relative humidity standard in the calibration of hygrometers. At 25 °C (77 °F) a saturated solution (45.8%) of the salt will yield an equilibrium relative humidity of 11.30%. Additionally, lithium chloride can itself be used as a hygrometer. This deliquescent salt forms a self solution when exposed to air. The equilibrium LiCl concentration in the resulting solution is directly related to the relative humidity of the air. The percent relative humidity at 25 °C (77 °F) can be estimated, with minimal error in the range 10–30 °C (50–86 °F), from the following first order equation: RH=107.93-2.11C, where C is solution LiCl concentration, percent by mass.

Molten LiCl is used for the prepration of carbon nanotubes, graphene and lithium niobate.

Precautions

Lithium salts affect the central nervous system in a variety of ways. While the citrate, carbonate, and orotate salts are currently used to treat bipolar disorder, other lithium salts including the chloride were used in the past. For a short time in the 1940s lithium chloride was manufactured as a salt substitute, but this was prohibited after the toxic effects of the compound were recognized.

See also

• Lithium chloride (data page)
• Solubility table

References

• Handbook of Chemistry and Physics, 71st edition, CRC Press, Ann Arbor, Michigan, 1990.
• N. N. Greenwood, A. Earnshaw, Chemistry of the Elements, 2nd ed., Butterworth-Heinemann, Oxford, UK, 1997.
• R. Vatassery, titration analysis of LiCl, sat'd in Ethanol by AgNO₃ to precipitate AgCl(s). EP of this titration gives %Cl by mass.
• H. Nechamkin, The Chemistry of the Elements, McGraw-Hill, New York, 1968.