Discovery

(English, soda; Medieval Latin, sodanum, headache remedy) Long recognized in compounds,sodium was first isolated by Davy in 1807 by electrolysis of caustic soda.

Sources

Sodium is present in fair abundance in the sun and stars. The D lines of sodium areamong the most prominent in the solar spectrum. Sodium is the fourth most abundant elementon earth, comprising about 2.6% of the earth's crust; it is the most abundant of thealkali group of metals.

It is now obtained commercially by the electrolysis of absolutely dry fused sodiumchloride. This method is much cheaper than that of electrolyzing sodium hydroxide, as wasused several years ago.

Uses
Sodium chloride is important for animal nutrition. Sodium compounds are used in the glass, soap, paper, textile, chemical, petroleum, and metal industries. Metallic sodium is used in manufacturing of sodium peroxide, sodium cyanide, sodamide, and sodium hydride. Sodium is used in preparing tetraethyl lead. It is used in the reduction of organic esters and preparation of organic compounds. Sodium metal may be used to improve the structure of some alloys, to descale metal, and to purify molten metals. Sodium, as well as NaK, an alloy of sodium with potassium, are important heat transfer agents.