Title: Sodium
CAS Registry Number: 7440-23-5
Additional Names: Natrium
Literature References: Na; at. no. 11; at. wt 22.98976928; valence 1. Group IA (1). Alkali metal. Occurrence in earth's crust: 2.83% by wt; principal cation in hydrosphere. Naturally occurring isotope: 23 (100%); radioactive isotopes (mass number): 19-22; 24-35. Prepd by Davy in 1807 by electrolysis of fused sodium hydroxide. Found in form of its compds, halides, silicates, carbonates; does not occur free. Industrial prepns primarily in Downs cells, also in Castner cells: Batsford, Chem. Metall. Eng. 26, 888, 932 (1932); Regelsberger, Chemische Technologie der Leichtmetalle Leipzig, 1926; Hardie, Ind. Chem. 30, 161 (1954). Reviews: ACS Monograph Series no. 133, entitled "Sodium," M. Sittig, Ed. (Reinhold, New York, 1956); Whaley, "Sodium, Potassium, Rubidium, Cesium and Francium" in Comprehensive Inorganic Chemistry Vol. 1, J. C. Bailar, Jr. et al., Eds. (Pergamon Press, Oxford, 1973) pp 369-529; Chemistry of the Elements N. N. Greenwood, A. Earnshaw, Eds. (Pergamon Press, New York, 1984) pp 75-116; C. H. Lemke, V. H. Markant in Kirk-Othmer Encyclopedia of Chemical Technology vol. 22 (Wiley-Interscience, New York, 4th ed., 1997) pp 327-354.
Properties: Light, silvery-white metal; body-centered cubic structure; lustrous when freshly cut; tarnishes on exposure to air, becoming dull and gray. Soft at ordinary temp, fairly hard at -20°. mp 97.82°; bp 881.4°; d20 0.968. Heat capacity of solid: 0.292 cal/g deg; heat capacity of liquid at mp: 0.331 cal/g deg. Heat of fusion: 27.05 cal/g; thermal conductivity (cal/sec °C cm): 0.205 (97.82°) 0.170 (400°). E0 (aqueous) Na/Na+ 2.714 V. Violently decomposes water, forming sodium hydroxide and hydrogen which may ignite spontaneously. Decomposes alc. Reacts vigorously with oxygen, burning with a yellow flame. Emits characteristic yellow color (589.2 nm) in flame. Combines directly with the halogens, with phosphorus. Reduces most oxides to the elemental state, reduces metallic chlorides. Dissolves in liq ammonia to give a blue soln; when heated in ammonia gas yields sodamide. Dissolves in mercury, forming sodium amalgam. Keep under liquids contg no oxygen, such as kerosene, naphtha.
Melting point: mp 97.82°
Boiling point: bp 881.4°
Density: d20 0.968
CAUTION: Direct contact with metal be may corrosive and cause skin and eye burns. See: Fire Protection Guide to Hazardous Materials (National Fire Protection Assoc., Quincy, MA, 12th ed., 1997) Section 49, p 117.
Use: Manuf of sodium compds, such as the cyanide, azide, peroxide, etc.; manuf of tetraethyllead; manuf of refractory metals; in org syntheses; for photoelectric cells; in sodium lamps; as catalyst for many polymerization reactions. Alloyed with potassium in heat transfer media. |