Glucinum. Be; at. wt 9.01218; at. no. 4; valence 2; Group 2a. Estimates of abundance in earth's crust vary from 2 to 10 ppm. Natural isotopes: 9 (100%); radioactive isotopes (mass numbers): 6-8; 10-12. Oxide discovered by Vauquelin in 1797; free metal isolated by Wöhler and Bussy in 1828. Produced industrially from beryl (3Be0.Al2O3.6SiO2); also found in phenacite (Be2SiO4), chrysoberyl (BeO.Al2O3). Precious form 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: Pinto, 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; J. Ballance et al., in Kirk-Othmer Encyclopedia of Chemical Technology vol. 3, (Wiley-Interscience, New York, 3rd ed., 1978) pp 803-823. Review of carcinogenicity studies of beryllium and beryllium compds: IARC Monographs 1, 17-28 (1972); ibid. 23, 143-204 (1980). Review of health effects of beryllium and its comps: Beryllium: Its Industral Hygiene Aspects, H. E. Stokinger, Ed. (Academic Press, New York, 1966) 318 pp.

Gray metal; close-packed hexagonal structure; anisotropic; high permeability to X-rays. 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.

Caution: Death may result from short exposure to very low concns of the element and its salts. Contact dermatitis, chemical conjunctivitis, corneal burns, non-healing ulceration at site of injury, subcutaneous nodules may occur following exposure. Acute: Pneumonitis may result from single exposure to beryllium and occasionally is fatal. Chronic: Pulmonary granulomatous disease may appear in 3 months to 15 years, often after a short exposure to low concn. Uncertainty as to complete recovery. Death rate about 25%. See: J. Schubert, "Beryllium and Berylliosis" in Sci. Am. 199, no. 2, pp 27-33 (1958). This substance and certain beryllium compounds may reasonably be anticipated to be carcinogens: Fourth Annual Report on Carcinogens (NTP 85-002, 1985) p 42.

USE: Source of neutrons when bombarded with alpha particles according to the equation 94Be + 4 2He --> 126 C +1on. 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 radio tube parts. In aerospace structures. In inertial guidance systems.