Lithium chloride

Lithium chloride
General
Molecular formula	LiCl
Molar mass	42.39 g/mol
Appearance	White crystalline solid
CAS number	(anhydrous) [85144-11-2 (hydrate)
Hydrates	monohydrate, trihydrate
Properties
Density and phase	2.07 g/cm³, solid
Solubility in water	63.7 g/100 ml (0 °C)
In ethanol In acetone	42.4 g/100 ml (25 °C) 4.11 g/100 ml (25 °C)
Melting point	605 °C (878 K)
Boiling point	>1300 °C (>1570 K)
Structure
Coordination geometry	Octahedral
Crystal structure
Dipole moment	7.13 D (gas)
Hazards
MSDS	External MSDS
Main hazards	Irritant
R/S statement	R: 22-36/37/38 S: 26-36/37/39
RTECS number	OJ5950000 (anhydrous)
Supplementary data page
Structure & properties	n, ε_r, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Other anions	lithium fluoride
Other cations	sodium chloride
Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) Chemical infobox

Lithium chloride behaves as a fairly typical ionic compound, although the Li⁺ ion is very small. The salt is hygroscopic and highly soluble in water, and is highly polar. It is more soluble in polar organic solvents such as methanol and acetone than is sodium chloride or potassium chloride.

Chemical properties

Lithium chloride can react as a source of chloride ion. As with any other soluble ionic chloride, it will precipitate insoluble chlorides when added to a solution of an appropriate metal salt such as lead(II) nitrate:

2 LiCl(aq) + Pb(NO₃)₂(aq) → PbCl₂(s) + 2 LiNO₃(aq)

The Li⁺ ion acts as a weak Lewis acid under certain circumstances; for example one mole of lithium chloride is capable of absorbing up to four moles of ammonia.

Solubility of LiCl in various solvents (g LiCl / 100g of solvent at 25° C)
H₂O	55
Liquid ammonia	3.02
Liquid sulfur dioxide	0.012
Methanol	21 - 41
Formic acid	27.5
Sulfolane	1.5
Acetonitrile	0.14
Acetone	0.83
Formamide	28.2
Dimethylformamide	11 - 28
Reference: Burgess, J. Metal Ions in Solution (Ellis Horwood, New York, 1978) ISBN 0853120277

Preparation

Lithium chloride may be prepared most simply by reaction of lithium hydroxide or lithium carbonate with hydrochloric acid. It may also be prepared by the highly exothermic reaction of lithium metal with either chlorine or anhydrous hydrogen chloride gas. Anhydrous LiCl is prepared from the hydrate by gently heating under an atmosphere of hydrogen chloride, used to prevent hydrolysis.

Uses

Lithium chloride is used for the production of lithium metal, by electrolysis of a LiCl/KCl melt at 450 °C. LiCl is also used as a brazing flux for aluminium in automobile parts.

Precautions

Irritant. Avoid swallowing.

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.
H. Nechamkin, The Chemistry of the Elements, McGraw-Hill, New York, 1968.

External links

Chlorides | Lithium compounds | Metal halides