Sodium, discovered by davy in 1807, is a soft, chemically reactive metal with a density of 0.97 G cm-3 and a melting point of 97.8B c. Metallic sodium is currently produced by the electrolysis of molten sodium chloride in the downs cell, a process that was patented in 1924. The cell contains an anode and a cathode chamber with collectors to recover the chlorine gas that is evolved. The castner cell, used exclusively until the 1920's, produced metallic sodium by the electrolysis of sodium hydroxide. This technique is still used in some areas of the world.
Sec. in Encyclopedia, of Marterials Sci. & Eng., Mit Press, V. 6 (R- s), 1986, P. 4465