Beryllium: A Chronic Problem.

Beryllium is the fourth element in the periodic table and the second lightest metal known. Discovered as an oxide in 1798 by the French chemist L. N. Vauquelin, beryllium was first isolated in 1828, when it was called "glucinium" owing to the sweet taste of its salts. Beryllium is the lightest of all solid, chemically stable substances and has an unusually high melting point (12870C). Silver gray and of low density (about onethird that of aluminum), with a close-packed hexagonal crystalline structure, beryllium metal has a very high strength-to-weight ratio. Although it is lighter than aluminum, it is 40% more rigid than steel. Beryllium has excellent electrical and thermal conductiveness but relatively pronounced brittleness, which restricts its applications. Principal uses of beryllium stem from the discovery in the 1920s that an addition