|Boiling Point: 3243°K, 2970°C, 5378°F
Melting Point: 1551°K, 1278°C, 2332°F
Electrons Energy Level: 2, 2
Isotopes: 8 + 1 Stable
Heat of Vaporization: 292.4 kJ/mol
Heat of Fusion: 12.2 kJ/mol
Density: 1.848 g/cm3 @ 300°K
Specific Heat: 1.82 J/g°K
Atomic Radius: 1.4Å
Ionic Radius: 0.35Å
Electronegativity: 1.57 (Pauling); 1.47 (Allrod Rochow)
|The name Beryllium
comes from the Greek, beryllos, beryl, from Prakrit, veruliya, from Pali, veuriya;
possibly from or simply akin to a Dravidian source represented by Tamil, veiruor, viar,
"to whiten, become pale". At one time Beryllium was referred to as glucinium
(from Greek, glykys, sweet), due to the sweet taste of its salts, which are toxic.
The chemical symbol suggested at that time was "Gl"). This
element was discovered by Louis Vauquelin in 1798 as the oxide in gemstone Beryl and in
Emeralds. Friedrich Wohler and A.A. Bussy independently isolated the metal in 1828
by reacting Potassium and Beryllium Chloride.
The element is a high-melting, silver-white metal which is the first member of the alkaline earth metals. It is not abundant in the environment and occurs mainly in the mineral Beryl with Aluminum and Silicon. It is used in specialty alloys such as spring metal in which it increases toughness.
The chief mineral source of Beryllium is also the same material of which Emeralds are formed. High quality Beryl crystals with Chromium impurities have an exquisite green color which has been valued for thousands of years.
A bivalent element, elemental Beryllium is a steel grey, strong, light-weight yet brittle, alkaline earth metal. It is primarily used as a hardening agent in alloys (most notably Beryllium Copper).
It has the highest melting points of the light metals. The modulus of eleasticity of Beryllium is approximately 1/3 greater than that of steel. It has excellent thermal conductivity, is nonmagnetic and resists attack by concentrated Nitric Acid, HNO3, It is highly permeable to X-rays, and neurons are liberated when it is hit by alpha particles, as from Radium or Polonium (about 30 neutrons/million alpha particles). At standard temperature and pressures Beryllium resists oxidation when exposed to air (although its ability to scratch glass is probably due to the formation of a thin layer of the oxide). The speed of sound in beryllium (12,500 m/s) is greater than in any other element.
Beryllium is an essential constituent of about 100 out of about 4000 known minerals, the most important of which are Bertrandite (Be4Si2O7(OH)2), Beryl (Al2Be3Si6O18), Chrysoberyl (Al2BeO4), and Phenakite (Be2SiO4). Precious forms of Beryl are Aquamarine and Emerald.
The most important commercial sources of Beryllium and its compounds are Beryl and Bertrandite. Beryllium metal did not become readily available until 1957. Currently, most production of this metal is accomplished by reducing Beryllium Fluoride with Magnesium metal. The price on the US market for vacuum-cast Beryllium ingots was $338 per pound ($745/kg) in 2001.
BeF2 + Mg MgF2 + Be
|Bertrandite, Be4Si2O7(OH)2||Beryl, Al2Be3Si6O18|
|Chrysoberyl, Al2BeO4||Phenakite, Be2SiO4|
|Beryllium Fluoride, BeF2||Beryllium Chloride, BeCl2|
Of beryllium's isotopes, only 9Be is stable. Cosmogenic 10Be is produced in the atmosphere by cosmic ray spallation of Oxygen and Nitrogen. Because Beryllium tends to exist in solution at pH levels less than about 5.5 (and most rainwater has a pH less than 5), it will enter into solution and be transported to the Earth's surface via rainwater. As the precipitation quickly becomes more alkaline, Beryllium drops out of solution. Cosmogenic 10Be thereby accumulates at the soil surface, where its relatively long half-life (1.51 million years) permits a long residence time before decaying to 10B. 10Be and its daughter products have been used to examine soil erosion, soil formation from regolith, the development of lateritc soils, as well as variations in solar activity and the age of ice cores.
The fact that 7Be and 8Be are unstable has profound cosmological consequences as it means that elements heavier than Beryllium could not be produced by nuclear fusion in the Big Bang. Moreover, the nuclear energy levels of 8Be are such that carbon can be produced within stars, thus making life possible.
The shortest-lived known isotope of Beryllium is 13Be which decays through neutron emission. It has a half-life of 2.7 × 10-21 seconds. 6Be is also very short-lived with a half-life of 5.0 × 10-21 seconds.
The exotics 11Be and 14Be are known to exhibit a nuclear halo.
|Be10||10.0135||1.51E 6 years|
|Beryllium and its salts are toxic substances and potentially carcinogenic. Chronic Berylliosis is a pulmonary and systemic granulomatous disease caused by exposure to Beryllium.|
Acute Beryllium disease in the form of chemical pneumonitis was first reported in Europe in 1933 and in the United States in 1943. Cases of chronic Berylliosis were first described in 1946 among workers in plants manufacturing fluorescent lamps in Massachusetts. Chronic Berylliosis resembles sarcoidosis in many respects, and the differential diagnosis is often difficult.
Although the use of Beryllium compounds in fluorescent lighting tubes was discontinued in 1949, potential for exposure to Beryllium exists in the nuclear and aerospace industries and in the refining of Beryllium metal and melting of Beryllium-containing alloys, the manufacturing of electronic devices, and the handling of other Beryllium-containing material.
Early researchers tasted Beryllium and its various compounds for sweetness in order to verify its presence. Modern diagnostic equipment no longer necessitates this highly risky procedure and no attempt should be made to ingest this substance. Beryllium and its compounds should be handled with great care and special precautions must be taken when carrying out any activity which could result in the release of Beryllium dust (lung cancer is a possible result of prolonged exposure to Beryllium laden dust).
This substance can be handled safely if certain procedures are followed. No attempt should be made to work with Beryllium before familiarization with correct handling procedures.
A successful test for Beryllium on different surface areas has been recently developed. The procedure uses fluorescence when Beryllium is bound to Sulfonated Hydroxybenzoquinoline to detect up to 10 times lower than the recommended limit for Beryllium concentration in the work place. Fluorescence increases with increasing Beryllium concentration. The new procedure has been successfully tested on a variety of surfaces.
Beryllium can be harmful if inhaled and the effects depend on period of exposure. If Beryllium air levels are high enough (greater than 100 µg/m³), an acute condition can result, called acute Beryllium disease, which resembles pneumonia. Occupational and community air standards are effective in preventing most acute lung damage. Long term exposure to Beryllium can increase the risk of developing lung cancer. The more common and serious health hazard from Beryllium today is Chronic Beryllium Disease (CBD). It continues to occur in industries as diverse as metal recycling, dental laboratories, alloy manufacturing, nuclear weapons production, defense industries, and metal machine shops that work with alloys containing small amounts of Beryllium.
Chronic Beryllium Disease (CBD)
Some people (1-15%) become sensitive to Beryllium. These individuals may develop an inflammatory reaction that principally targets the respiratory system and skin. This condition is called Chronic Beryllium Disease (CBD), and can occur within a few months or many years after exposure to higher than normal levels of Beryllium (greater than 0.02 µg/m³). This disease causes fatigue, weakness, night sweats and can cause difficulty in breathing and a persistent dry cough. It can result in anorexia, weight loss, and may also lead to right-side heart enlargement and heart disease in advanced cases. Some people who are sensitized to Beryllium may not have any symptoms. The disease is treatable but not curable. CBD occurs when the body's immune system recognizes Beryllium particles as foreign material and mounts an immune system attack against the particles. Because these particles are typically inhaled into the lungs, the lungs becomes the major site where the immune system responds. The lungs become inflamed, filled with large numbers of white blood cells that accumulate wherever Beryllium particles are found. The cells form balls around the Beryllium particles called "granulomas." When enough of these granulomas develop, they interfere with the normal function of the organ. Over time, the lungs become stiff and lose their ability to help transfer Oxygen from the air into the bloodstream. Patients with CBD develop difficulty inhaling and exhaling sufficient amounts of air and the amount of Oxygen in their bloodstreams falls. Treatment of such patients includes use of Oxygen and medicines that try to suppress the immune system's over-reaction to Beryllium. A class of immunosuppressive medicines called Glucocorticoids (example: Prednisone), is most commonly used as treatment. The general population is unlikely to develop Acute or Chronic Beryllium Disease because ambient air levels of Beryllium are normally very low (0.00003-0.0002 µg/m³).
Swallowing Beryllium has not been reported to cause effects in humans because very little Beryllium is absorbed from the stomach and intestines. Ulcers have been seen in dogs ingesting Beryllium in the diet. Beryllium contact with skin that has been scraped or cut may cause rashes or ulcers, or bumps under the skin called "granulomas."
Effects on Children
There are no studies on the health effects of children exposed to Beryllium, although individual cases of CBD have been reported in children of Beryllium workers from the 1940s. It is likely that the health effects seen in children exposed to Beryllium will be similar to the effects seen in adults. It is unknown whether children differ from adults in their susceptibility to Beryllium. It is unclear whether Beryllium is teratogenic.
Detection in the Body
Beryllium can be measured in the urine and blood. The amount of Beryllium in blood or urine may not indicate time or quantity of exposure. Beryllium levels can also be measured in lung and skin samples. While such measurements may help establish that exposure has occurred, other tests are used to determine if that exposure has resulted in health effects. A blood test, the blood Beryllium lymphocyte proliferation test (BeLPT), identifies Beryllium sensitization and has predictive value for CBD. The BeLPT has become the standard test for detecting Beryllium sensitization and CBD in individuals who are suspected of having CBD and to help distinguish it from similar conditions such as sarcoidosis. It is also the main test used in industry health programs to monitor whether disease is occurring among current and former workers who have been exposed to Beryllium on the job. The test can detect disease that is at an early stage, or can detect disease at more advanced stages of illness as well. The BeLPT can also be performed using cells obtained from a person's lung by a procedure called "bronchoscopy."
Industrial Release Limits
Typical levels of Beryllium that industries may release into the air are of the order of 0.01 µg/m³, averaged over a 30-day period, or 2 µg/m³ of workroom air for an 8-hour work shift. Compliance with the current U.S. Occupational Safety and Health Administration (OSHA) permissible exposure limit for Beryllium of 2 µg/m³ has been determined to be inadequate to protect workers from developing beryllium sensitization and CBD. The American Conference of Governmental Industrial Hygienists (ACGIH), which is an independent organization of experts in the field of occupational health, has proposed a threshold limit value (TLV) of 0.05 µg/m³ in a 2006 Notice of Intended Change (NIC). This TLV is 40 times lower than the current OHSA permissible exposure limit, reflecting the ACGIH analysis of best available peer-reviewed research data concerning how little airborne Beryllium is required to cause sensitization and CBD. Because it can be difficult to control industrial exposures to Beryllium, it is advisable to use any methods possible to reduce airborne and surface contamination by Beryllium, to minimize the use of Beryllium and Beryllium-containing alloys whenever possible, and to educate people about the potential hazards if they are likely to encounter beryllium dust or fumes.
Atomic Radius (Å): 1.4Å
Electrochemical Equivalents: 0.16812 g/amp-hr
Atomic Mass Average: 9.012182
(Gr. beryllos, beryl; also called Glucinium or Glucinum, Gr. glykys, sweet) Discovered as the oxide by Vauquelin in beryl and in emeralds in 1798. The metal was isolated in 1828 by Wohler and by Bussy independently by the action of potassium on beryllium chloride. Beryllium is found in some 30 mineral species, the most important of which are bertrandite, beryl, chrysoberyl, and phenacite. Aquamarine and emerald are precious forms of beryl. Beryl and bertrandite are the most important commercial sources of the element and its compounds. Most of the metal is now prepared by reducing beryllium fluoride with magnesium metal. 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 lightest of all metals, and has one of the highest melting points of the light metals. Its modulus of elasticity is about one third greater than that of steel. It resists attack by concentrated nitric acid, has excellent thermal conductivity, and is nonmagnetic. It has a high permeability to X-rays and when bombarded by alpha particles, as from radium or polonium, neutrons are produced in the amount of about 30 neutrons/million alpha particles. At ordinary temperatures beryllium resists oxidation in air, although its ability to scratch glass is probably due to the formation of a thin layer of the oxide. 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. It has found application as a structural material for high-speed aircraft, missiles, spacecraft, and communication satellites. It is being used in the windshield frame, brake discs, support beams, and other structural components of the space shuttle. Because beryllium is relatively transparent to X-rays, ultra-thin Be-foil is finding use in X-ray lithography for reproduction of microminiature integrated circuits. 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 instruments where lightness, stiffness, and dimensional stability are required. The oxide has a very high melting point and is also used in nuclear work and ceramic applications. Beryllium and its salts are toxic and should be handled with the greatest of care. 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 if certain work codes are observed, but no attempt should be made to work with beryllium before becoming familiar with proper safeguards.
Source: CRC Handbook of Chemistry and Physics, 1913-1995. David R. Lide, Editor in Chief. Author: C.R. Hammond
Although emeralds and beryl were known to ancient civilizations, they were first recognized as the same mineral (Be3Al2(SiO3)6) by Abbé Haüy in 1798. Later that year, Louis-Nicholas Vauquelin, a French chemist, discovered that an unknown element was present in emeralds and beryl. Attempts to isolate the new element finally succeeded in 1828 when two chemists, Friedrich Wölhler of Germany and A. Bussy of France, independently produced beryllium by reducing beryllium chloride (BeCl2) with potassium in a platinum crucible. Today, beryllium is primarily obtained from the minerals beryl (Be3Al2(SiO3)6) and bertrandite (4BeO·2SiO2·H2O) through a chemical process or through the electrolysis of a mixture of molten beryllium chloride (BeCl2) and sodium chloride (NaCl).
Beryllium is relatively transparent to X-rays and is used to make windows for X-ray tubes. When exposed to alpha particles, such as those emitted by radium or polonium, beryllium emits neutrons and is used as a neutron source. Beryllium is also used as a moderator in nuclear reactors.
Beryllium is alloyed with copper (2% beryllium, 98% copper) to form a wear resistant material, known as beryllium bronze, used in gyroscopes and other devices where wear resistance is important. Beryllium is alloyed with nickel (2% beryllium, 98% nickel) to make springs, spot-welding electrodes and non-sparking tools. Other beryllium alloys are used in the windshield, brake disks and other structural components of the space shuttle.
Beryllium oxide (BeO), a compound of beryllium, is used in the nuclear industry and in ceramics.
Beryllium was once known as glucinum, which means sweet, since beryllium and many of its compounds have a sugary taste. Unfortunately for the chemists that discovered this particular property, beryllium and many of its compounds are poisonous and should never be tasted or ingested.