Lithium

Lithium, Na, is a Alkali Metal element, found in Group Ia of the periodic table.

Atomic Number : 3
Atomic Mass : 6.94

Discovery

Lithium was discovered by Arfvedson in 1817AD.

Lithium, Li, first isolated by Bunsen and Matthiessen in 1855AD by the electrolysis of fused lithium chloride.

Occurrence

Lithium is a rare metallic element, but it is widely distributed. The principal ores are

Lepidolite,
Spodemene, Li2O.Al2O3.4SiO2, and
Amblygonite, Li(ALF)PO4.

Manufacture

Lithium metal is prepared by the electrolysis of fused lithium chloride.

Properties

Lithium is

a soft silvery-white lustrous metal, which can be easily cut with a knife,
is highly reactive and tarnished readily in air due to the formation of a layer of lithium suboxide on the surface of the metal, and
burns in air with the same brilliance of the magnesium flame.

Reactions

The chemical properties of lithium resemble those of sodium, but its reactions are the least reactive for the alkali metals group. However, lithium is still highly reactive chemically, and must be stored under liquid paraffin, which contains no oxygen, to prevent oxidation.

Lithium burns readily in air forming a mixture of lithium suboxide.


		4 Li    +    O2    ==>    2 Li2O

Lithium reacts readily with the halogens, forming the appropriate lithium salt.


		2 Li    +    Cl2    ==>    2 LiCl

Lithium reacts violently with water, forming lithium hydroxide and liberating hydrogen.


		2 Li    +    2 H2O    ==>    2 LiOH    +    H2(g)

Uses

Lithium is used

in medicine in the treatment of gout, as lithium urate is one of the few soluble salts of uric acid,
in medicine in the treatment of some mental disorders,
in the manufacture of lithium hydride batteries, which are used in portable computers and other electronic equipment, and
as a reducing agent, usually in the form of lithium aluminium hydride, LiAlH4, in organic chemistry.

Detection and Analysis

Lithium is detected in its compounds by the characteristic red colouration which it imparts to flames when burned and by spectroscopic methods.

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