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A soft, malleable metallic element. Sodium is found as salts (carbonates, chlorides, etc.) and has an abundance of 2.9% in the earth's crust. It was first isolated by Sir Humphrey Davy in 1807 by the electrolysis of Sodium hydroxide. Sodium is a silvery-white metal that can be cut with a knife. It oxidizes quickly in air and reacts violently with water. Sodium compounds are used universally for electrolytic reactions, as well as for seasoning and preserving food and skins. Metallic sodium is used as a coolant in nuclear reactors and to produce the bright yellow color of Sodium vapor lamps.

Synonyms and Related Terms

Na; natrium (Lat., Ned., Deut., Sven.); natrum; sodio (It., Esp.); Sódio (Port.)


  • Severe fire risk in contact with water; extinguish fires with dry soda or salt.
  • Ignites spontaneously in dry air. Corrosive on contact with skin.
  • United Nuclear: MSDS

Physical and Chemical Properties

Flame color is bright yellow. Reacts violently with water to form sodium hydroxide and evolve hydrogen. Dissolves in liquid ammonia to form blue solution. Insoluble in benzene, kerosene and naphtha.

Composition Na (atomic no. 11)
CAS 7440-23-5
Melting Point 97.6 - 97.8 C
Density 0.967-0.971 g/ml
Molecular Weight atomic wt = 22.98977
Boiling Point 881-892 C

Resources and Citations

  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: pps. 24, 735
  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
  • Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
  • Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
  • The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 8710
  • The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998

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