por What is beryllium?
He beryllium It is a metallic element that belongs to group 2 or IIA of the periodic table. It is the lightest alkaline earth metal in the group, and is represented by the symbol Be. Its atom and cation are also smaller than those of its congeners (Mg, Ca, Sr…).
Due to its unusual charge density, this metal does not usually occur in isolation. Nearly 30 minerals that contain it are known, among which are beryl (3BeO·Al2O3·6SiO2·2H2O), bertrandite (4BeO.2SiO2.2H2O), chrysoberyl (BeAl2O4), and phenakite (Be2Si4).
Emerald, a precious stone, is a variant of beryl. However, pure beryllium is not so flashy: it has pale grayish sheens and has been obtained in the form of nuggets or dragees.
Beryllium has a set of characteristic physical properties. It has a low density, high thermal and electrical conductances, as well as its thermal capacity and heat dissipation, it is not a magnetic metal, and it also possesses an appropriate combination of rigidity and elasticity.
All these properties have led beryllium to be a metal with many applications, ranging from its use in alloys with copper for the manufacture of tools, to its use in rockets, airplanes, automobiles, nuclear reactors, X-ray equipment, resonance nuclear magnetic etc.
Beryllium has 10 known isotopes, ranging from 5Be to 14Be, with 9Be being the only stable one. Likewise, it is a very toxic metal, which especially affects the respiratory system, so there is a limitation in its use.
discovery of beryllium
Beryllium was discovered by Louis-Nicolas Vauguelin in 1798 as a compositional element of the mineral beryl, and a beryllium aluminum silicate.
Later, the German chemist Frederic Wöhler, in 1828, managed to isolate it by reacting potassium with beryllium chloride in a platinum crucible.
Simultaneously, and independently, the French chemist Antoine Bussy also achieved the isolation of beryllium. Wöhler was the one who suggested the name beryllium for the metal.
It received its current name in 1957, since it was previously known as glucinium, due to the sweet taste of some of its salts. But to avoid confusion with other sweet-tasting compounds, and with a plant called glycine, it was decided to change the name to beryllium.
beryllium structure
Being beryllium the lightest of the alkaline earth metals, the volume of its atoms is the smallest of all. The beryllium atoms interact with each other through the metallic bond, in such a way that their “sea of electrons” and the repulsions between the nuclei model the structure of the resulting crystal.
Black beryllium crystals are then formed. These crystals have a hexagonal structure (top image), where each Be atom has six lateral neighbors, and another three in the planes above and below.
As the crystals are black, it is useful to imagine that the black dots in the hexagonal structure are replaced by beryllium atoms. This is one of the most compact structures a metal can adopt, and it makes sense that such small Be atoms would “squeeze together” so much to avoid the least amount of void or number of holes between them.
Electron configuration of beryllium
1s22s2
Which is equal to 4 electrons, of which 2 are valence. If an electron is promoted to the 2p orbital, we will have two sp hybrid orbitals. Thus, in beryllium compounds there can be linear geometries, X-Be-X. For example, the isolated molecule of BeCl2, Cl-Be-Cl.
beryllium properties
Physical description. Brittle, shiny, steel-gray solid.
Melting point. 1287ºC.
Boiling point. 2471ºC.
Density. 1.848 g/cm3 at room temperature. 1.69 g/cm3 to the melting point (liquid state).
Atomic radio. 112 p.m.
covalent radius. 90 p.m.
atomic volume. 5 cm3/mol.
Specific heat. 1.824 J/g mol at 20ºC.
heat of fusion. 12.21kJ/mol.
heat of evaporation. 309 kJ/mol.
electronegativity. 1.57 on the Pauling scale.
standard potential. 1.70V
Speed of sound. 12,890m/s.
Thermal expansion. 11.3 µm/m K at 25ºC.
Thermal conductivity. 200 w/m K.
Chemical properties. The beryllium is covered with a layer of beryllium oxide (BeO) that serves as protection in air at room temperature. Beryllium oxidation occurs at temperatures above 1,000 ºC, producing beryllium oxide and beryllium nitride as products. It is resistant to the action of 15 M nitric acid. But it dissolves in hydrochloric acid and in alkalis, such as sodium hydroxide.
beryllium applications
Tool making. Beryllium forms alloys with copper, nickel, and aluminum. In particular, the alloy with copper produces tools of great hardness and resistance, constituting only 2% of the weight of the alloy. These tools do not produce sparks when striking iron, which makes them suitable for use in environments with a high content of combustible gases. Due to its low density it is light in weight, which, together with its rigidity, allows its use in spacecraft, rockets, missiles and airplanes. The alloy with beryllium has been used in the manufacture of automobile parts. Also in the elaboration of springs. Due to the great hardness that beryllium gives to its alloys, they have been used in the brakes of military aircraft.
mirror making. It is used in the production of mirrors due to its dimensional stability and its ability to have a high polishability. These mirrors are used in satellites and in fire control systems. Also in space telescopes.
In ionizing radiation. It is a low-density element, which is why it is transparent to X-rays. This characteristic allows its application in the construction of the windows of the tubes that produce X-rays, for industrial application and in medical diagnosis. It is also used in the windows of radioactive emission detectors.
In magnetism generating equipment. Since it is not a magnetic element, it is used in the manufacture of magnetic resonance equipment items, in which high intensity magnetic fields are generated, minimizing any interference.
Nuclear reactors. Due to its high melting point, it has found application in nuclear reactors and in ceramics. Beryllium is used as a moderator of nuclear reactions and as a producer of neutrons:
9Be + 4He (α) => 12C + n (neutron)
nuclear reactions. It is estimated that for one million beryllium atoms bombarded with α particles, up to 30 million neutrons are produced. Precisely this nuclear reaction allowed the discovery of the neutron. James Chadwick bombarded beryllium atoms with α (He) particles. The researcher observed the release of subatomic particles, without an electrical charge, which led to the discovery of neutrons.
metal protector. Adding a quantity of beryllium to the surface of metals that can oxidize gives them some protection. For example, the flammability of magnesium is reduced and the brilliance of silver alloys is prolonged.
Where is beryllium found?
It is found in pegmatite, associated with mica, feldspar, and quartz. By using a flotation technique, it is possible to separate a mixture of beryl and feldspar. Subsequently, the feldspar and beryl are concentrated and subjected to a treatment with calcium hypochlorite.
Followed by a treatment with sulfuric acid and potassium sulfonate, through dilution, flotation of the beryl is achieved, separating it from the feldspar.
Beryl is treated with sodium fluorosilicate and soda at 770°C to form sodium fluoroberylate, aluminum oxide, and silicon dioxide. The beryllium hydroxide is then precipitated from the sodium fluoroberylate solution with sodium hydroxide.
Beryllium fluoride is formed by reacting beryllium hydroxide with ammoniacal hydrogen fluoride, producing ammonium tetrafluoroberylate. It is heated to form beryllium fluoride, which is hot treated with magnesium to isolate the beryllium.
Beryllium risks
Beryllium, as a finely divided metal, in the form of solutions, dry powder or fume, is highly toxic and can cause dermatitis. However, the greatest toxicity occurs by inhalation.
Initially, beryllium can induce a hypersensitivity or allergy, which can develop into berylliosis, or chronic beryllium disease (CBD). It is a serious disease, characterized by a decrease in lung capacity.
Acute disease is rare. In chronic disease there is granuloma formation throughout the body, especially in the lungs. Chronic berylliosis causes progressive dyspnea, cough, and general weakness.
Acute berylliosis can be deadly. In berylliosis, the progressive loss of respiratory function occurs, since there is obstruction in the flow of gases in the respiratory tract and decreased oxygenation of arterial blood.
References
Beryllium. Retrieved from rsc.org. Helmenstine, AM Beryllium Facts. Retrieved from thoughtco.com. Beryllium. Retrieved from en.wikipedia.org. Learn about the element beryllium Retrieved from beryllium.com. Beryllium. Recovered from britannica.com.