Lithium chloride

Lithium chloride
IUPAC name	Lithium chloride
Identifiers
CAS number	7447-41-8 Y, 85144-11-2 (x-hydrate) 404596-80-1
PubChem	4933294
RTECS number	OJ5950000
InChI	InChI=1/ClH.Li/h1H;/q;+1/p-1
InChI key	KWGKDLIKAYFUFQ-REWHXWOFAB
Properties
Molecular formula	LiCl
Molar mass	42.394(4) g/mol
Appearance	white solid hygroscopic [1]
Density	2.068 g/cm3 (anhydrous)
Melting point	605 °C
Boiling point	1382 °C (decomp)
Solubility in water	832 g/L (20 °C)
Solubility	highly soluble in alcohol, pyridine 4.1 g/100 mL (acetone)
Refractive index (nD)	1.662
Structure
Coordination geometry	Octahedral
Molecular shape	Linear (gas)
Dipole moment	7.13 D (gas)
Thermochemistry
Std enthalpy of formation ΔfHo298	-9.638 kJ/g
Specific heat capacity, C	1.132 J/(g K)
Hazards
MSDS	External MSDS
EU Index	Not listed
NFPA 704	0 2 0
Flash point	Non-flammable
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	n, εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
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 (83g/100 mL of water at 20 °C) and its hygroscopic properties.^[2]

Chemical properties

The salt forms crystalline hydrates, unlike the other alkali metal chlorides.^[3] Mono-, tri-, and pentahydrates are known.^[4] It also absorbs up to four equivalents of ammonia. 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. To minimize hydrolysis, 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 600 °C. LiCl is also used as a brazing flux for aluminium in automobile parts. It is used as a desiccant for drying air streams.^[2] 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.^[5]

It is used in the production of extremely sensitive mirrors for astronomy with its high flash point creating only a 1m divot if stretched over the surface of earth.

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

Precautions

Lithium salts affect the central nervous system; see lithium pharmacology for more details. 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.^[6][7][8]

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.

1. ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0070494398
2. ^ ^{a b} Ulrich Wietelmann, Richard J. Bauer "Lithium and Lithium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH: Weinheim.
3. ^ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
4. ^ Andreas Hönnerscheid, Jürgen Nuss, Claus Mühle, Martin Jansen "Die Kristallstrukturen der Monohydrate von Lithiumchlorid und Lithiumbromid" Zeitschrift für anorganische und allgemeine Chemie, 2003, volume 629, p. 312-316.doi: 10.1002/zaac.200390049
5. ^ Cathala, G., Savouret, J., Mendez, B., West, B.L., Karin, M., Martial, J.A., and Baxter, J.D. (1983). "A Method for Isolation of Intact, Translationally Active Ribonucleic Acid". DNA 2 (4): 329–335. PMID 6198133. 
6. ^ Talbott J. H. (1950). "Use of lithium salts as a substitute for sodium chloride". Arch Med Interna. 85 (1): 1–10. PMID 15398859. 
7. ^ L. W. Hanlon, M. Romaine, F. J. Gilroy. (1949). "Lithium Chloride as a Substitute for Sodium Chloride in the Diet". Journal of the American Medical Association 139 (11): 688–692. 
8. ^ "Case of trie Substitute Salt". TIME. 28 February 1949. http://www.time.com/time/magazine/article/0,9171,799873,00.html.