Title: Beryllium
CAS Registry Number: 7440-41-7
Additional Names: Glucinium
Literature References: Be; at. wt 9.012182; at. no. 4; valence 2. Group IIA (2). Alkaline earth metal. Estimated abundance in earth's crust 2 to 6 ppm. Natural isotopes (mass number): 9 (100%); known artificial radioactive isotopes: 6-8; 10-12. Oxide discovered by Vauquelin in 1797; free metal isolated by Wöhler and Bussy in 1828. Produced industrially from beryl (3BeO.Al2O3.6SiO2) and bertrandite (4BeO.2SiO2.H2O); also found in phenacite (Be2SiO4), chrysoberyl (BeO.Al2O3). Precious forms of beryl: emerald, aquamarine. Reviews of beryllium and its compounds: Kjellgren, "Beryllium" in Rare Metals Handbook, C. A. Hampel, Ed. (Reinhold, New York, 1954) pp 31-55; D. A. Everest, Chemistry of Beryllium (Elsevier, New York, 1964) 151 pp. Review of properties and use: N. P. Pinto, J. Greenspan, "Beryllium" in Modern Materials vol. 6, B. W. Gonser, Ed. (Academic Press, New York, 1968) pp 319-372; D. A. Everest, "Beryllium" in Comprehensive Inorganic Chemistry, J. C. Bailar, Jr. et al., Eds. (Pergamon Press, Oxford, 1973) pp 531-590; A. J. Stonehouse et al., in Kirk-Othmer Encyclopedia of Chemical Technology vol. 4 (Wiley-Interscience, New York, 4th ed., 1992) pp 126-146; A. J. Stonehouse, M. N. Emly, ibid. 147-153. Review of carcinogenic risk of beryllium and its compds: IARC Monographs 1, 17-28 (1972); ibid. 23, 143-204 (1980); of toxicology and human exposure: Toxicological Profile for Beryllium (PB2003-100135, 2002) 290 pp.; of immunotoxicology: A. L. Reeves, O. P. Preuss in Immunotoxicology and Immunopharmacology, J. H. Dean et al., Eds. (Raven Press, New York, 1985) pp 441-455; of human and environmental toxicology: WHO, Environ. Health Criter. 106, 1-210 (1990).
Properties: Gray, brittle metal; close-packed hexagonal structure; anisotropic; high permeability to X-rays; can serve as a neutron source through either (a,n) or (n,2n) reactions. Lightest of all solid and chemically-stable substances. Displays excellent electrical and thermal conductivities. mp 1287°. bp 2500° (extrapolated). d 1.8477. Heat capacity at constant pressure (30°) 0.437 cal/g/°C: Walker et al., J. Chem. Eng. Data 7, 595 (1962). Latent heat of fusion: 3.5 kcal/ mole. Brinell hardness: 60-125. Chemical properties similar to aluminum; metal resistant to attack by acid due to the formation of a thin oxide film. E° (aq) Be/Be2+ 1.85 V (calc.). Finely divided or amalgamated metal reacts with HCl, dil H2SO4 and dil HNO3; attacked by strong bases with evolution of H2.
Melting point: mp 1287°
Boiling point: bp 2500° (extrapolated)
Density: d 1.8477
CAUTION: Overexposure to beryllium and beryllium compounds has been associated with acute and chronic toxicity. Toxicity due to chronic inhalation is called "berylliosis" and appears after a latent period as an immunologically mediated, progressive, systemic disease leading to the formation of a characteristic granulomatous lesion. Potential symptoms of overexposure are anorexia, weight loss, weakness, chest pains, cough, clubbing of fingers, cyanosis, pulmonary insufficiency; direct contact may cause eye irritation. Dermal exposure may cause acute contact dermatitis; chronic dermal exposure may cause granulomatous skin ulceration. See Patty's Industrial Hygiene and Toxicology vol. 2C, G. D. Clayton, F. E. Clayton, Eds. (John Wiley & Sons, Inc., New York, 4th ed., 1994) pp 1930-1948; NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 28. Beryllium and beryllium compounds are listed as known human carcinogens: Report on Carcinogens, Eleventh Edition (PB2005-104914, 2004) p III-32.
Use: Source of neutrons when bombarded with alpha particles according to the equation 94Be + 42He ® 612C + 10n. This yields about 30 neutrons per million alpha particles. Also as neutron reflector and neutron moderator in nuclear reactors. In beryllium copper and beryllium aluminum alloys (by direct reduction of beryllium oxide with carbon in the presence of Cu or Al). In aerospace, aircraft and satellite structures; x-ray transmission windows; missile parts; nuclear weapons; fuel containers; precision instruments; rocket propellants; navigational systems; heat shields; and mirrors. For fiber optics and cellular network communications systems. |