Beryllium is a chemical element with the symbol Be and atomic number 4. It is a relatively rare element in the universe, usually occurring as a product of the spallation of larger atomic nuclei that have collided with cosmic rays. Within the cores of stars, It is depleted as it is fused into heavier elements. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl and chrysoberyl. As a free element it is a steel-gray, strong, lightweight and brittle alkaline earth metal.
In structural applications, the combination of high flexural rigidity, thermal stability, thermal conductivity and low density (1.85 times that of water) make Be metal a desirable aerospace material for aircraft components, missiles, spacecraft, and satellites. Because of its low density and atomic mass, It is relatively transparent to X-rays and other forms of ionizing radiation; therefore, it is the most common window material for X-ray equipment and components of particle detectors. The high thermal conductivities of Be and beryllium oxide have led to their use in thermal management applications. When added as an alloying element to aluminium, copper, iron or nickel beryllium improves many physical properties. Tools made of beryllium copper alloys are strong and hard and do not create sparks when they strike a steel surface. Beryllium does not form oxides until it reaches very high temperatures.
The commercial use of beryllium requires the use of appropriate dust control equipment and industrial controls at all times because of the toxicity of inhaled beryllium-containing dusts that can cause a chronic life-threatening allergic disease in some people called berylliosis.
The extraction from its compounds is a difficult process due to its high affinity for oxygen at elevated temperatures, and its ability to reduce water when its oxide film is removed. The United States, China and Kazakhstan are the only three countries involved in the industrial-scale extraction. It production technology is in early stages of development in Russia after a 20-year hiatus.
Be hydroxide created using either the sinter or melt method is then converted into beryllium fluoride or beryllium chloride. To form the fluoride, aqueous ammonium hydrogen fluoride is added to beryllium hydroxide to yield a precipitate of ammonium tetrafluoroberyllate, which is heated to 1,000 °C (1,830 °F) to form beryllium fluoride. Heating the fluoride to 900 °C with magnesium forms finely divided Be, and additional heating to 1,300 °C creates the compact metal. Heating Be hydroxide forms the oxide, which becomes beryllium chloride when combined with carbon and chlorine. Electrolysis of molten beryllium chloride is then used to obtain the metal.
It behaviour differs from the other alkaline earth metals because of its small size and high electronegativity.
- It compounds are predominantly covalent due to its high polarizing power and its salts are readily Hydrolyzed.
- It is not easily affected by dry air and does not decompose water at ordinary temperature.
- It is an amphoteric metal. It dissolves in alkali solutions forming beryllates.
- Its salts do not respond to the flame test while Ca, Sr, and Ba give characteristic flame colors.
- Be has a maximum covalency of 4 while other can have a maximum covalency of 6.