Beryllium

Beryllium is a Group 2 (IIA) element. It is a metal and has a high melting point. At ordinary temperatures, beryllium resists oxidation in air. Beryllium compounds are very toxic. Its ability to scratch glass is probably due to the formation of a thin layer of the oxide. Aquamarine and emerald are precious forms of the mineral beryl, [Be₃Al₂(SiO₃)₆].

Its chemistry is dominated by its tendency to lose an electron to form Be²⁺. As this ion is so small it is highly polarising, to the extent that its compounds are rather covalent. Its small size means that its complexes tend to be tetrahedral rahter than octahedral.

In fact, compounds containing beryllium are poisonous. Beryllium is found in a number of minerals. The most important minerals are beryl, [Be₃Al₂(SiO₃)₆], which is often found as hexagonal prisms, and bertrandite [4BeO.2SiO₂.H₂O]. Aquamarine and emerald are precious forms of beryl.