Beryllium is in the 2nd period. It is the lightest element of Group IIA, the alkaline earth metals. Other members of the group are magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).
Beryllium metal was identified as the oxide by Vauquelin in beryl (Be3Al2Si6O18) and in emeralds in 1798. The metal was isolated in 1828 by Wöhler and independently by Bussy by reducing beryllium chloride with potassium metal.
The name is derived from the Greek word, beryllos, which refers to the precious stone beryl, beryllium aluminum silicate (3BeO · Al2O3 · 6 SiO2), and the symbol Be is derived from the name. The element is also sometimes called glucinium or glucinum from the Greek word for sweet (glykys) because its compounds taste sweet.
Compounds of Be have a sweet taste, but acute pulmonary disease can result from inhaling dusts containing beryllium or its salts.
Beryllium is the only light metal (d = 1.846 g/cm3) that has a high melting point (1287°C). In the solid state the metal has a hexagonal closest packed structure.
At ordinary temperatures beryllium resists oxidation in air, most likely owing to the formation of a thin, impervious oxide coating; its ability to scratch glass is probably also due to this thin layer of the oxide.
Beryl is the most important commercial source of the element and its compounds. The metal is now usually prepared by reducing beryllium fluoride with magnesium metal.
BeF2(s) + 2 Mg(s) + heat Be(s) + MgF2(s)
Beryllium metal did not become readily available to industry until 1957. The metal, steel gray in color, has many desirable properties. It is one of the least dense of all metals, and has one of the highest melting points of the light metals. Its strength per pound is one third greater than that of steel, and it is used in many alloys in the aerospace industry. It has excellent thermal conductivity, is nonmagnetic, and has a high permeability to x-rays. This latter property makes it useful for windows in X-ray tubes. When bombarded by alpha particles, as from radium or polonium, neutrons are produced in the ratio of about 30 neutrons/million alpha particles.
Beryllium is used as an alloying agent in producing beryllium copper, which is extensively used for springs, electrical contacts, spot-welding electrodes, and nonsparking tools; the latter are used in oil refineries and other places where sparks constitute a fire hazard.
Beryllium is used in nuclear reactors as a reflector or moderator, for it has a low thermal neutron absorption cross-section. It is used in gyroscopes, computer parts, and inertial guidance instruments where lightness, stiffness, and dimensional stability are required.
Beryllium resists attack by liquid sodium and is therefore used in nuclear reactors where sodium is used as the coolant. The oxide has a very high melting point and is also used in nuclear work and ceramic applications.
Emerald and aquamarine are varieties of beryl. Phenakite, beryllium silicate (Be2SiO4), is another beryllium containing mineral.
Beryllium and its salts are toxic and should be handled with the great care. But for toxicity Be might be used as a rocket fuel; its combustion yields more heat per unit weight than any other element. Beryllium and its compounds should not be tasted to verify the sweetish nature of beryllium (as did early experimenters). The metal, its alloys, and its salts can be handled safely if certain work codes are observed, but no attempt should be made to work with beryllium before becoming familiar with proper safeguards.
The maximum allowable concentration of beryllium dust is recommended to be about 1-2 g/m3 in working areas or 0.01 micro-g/m3 in non-working areas. Beryllium toxicity apparently results because Be(II) can displace Mg(II) from Mg-activated enzymes. This happens because Be ions have greater coordinating power than Mg ions.