Helium (Greek word helios = sun) is a mono-atomic gas, lighter than air, colourless, non combustible, odourless and non toxic. Helium is zerovalent and has no known chemical combinations. Helium is obtained from helium containing natural gases. This takes place by cooling down the gas under partial condensation of the heavy fractions and coarse and fine purification of gas. Obtaining it from air through air decomposition is carried out only in areas which have little natural gas. Highly compressed, about 99% pure helium is available in gaseous form in steel bottles and in liquid form in tank containers. Helium is used for powder metallurgy as protective gas for avoiding oxide and nitride formation and also when manufacturing semiconductors and other electronic components. In refrigeration technology (cryogenics) liquid helium makes it possible to achieve low temperatures separated by only a few thousandths of a degree from absolute zero.
