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Encyclopedia > Boron
5 berylliumboroncarbon
-

B

Al
General
Name, symbol, number boron, B, 5
Chemical series metalloids
Group, period, block 132, p
Appearance black/brown
Standard atomic weight 10.811(7) g·mol−1
Electron configuration 1s2 2s2 2p1
Electrons per shell 2, 3
Physical properties
Phase solid
Density (near r.t.) 2.34 g·cm−3
Liquid density at m.p. 2.08 g·cm−3
Melting point 2349 K
(2076 °C, 3769 °F)
Boiling point 4200 K
(3927 °C, 7101 °F)
Heat of fusion 50.2 kJ·mol−1
Heat of vaporization 480 kJ·mol−1
Specific heat capacity (25 °C) 11.087 J·mol−1·K−1
Vapor pressure
P/Pa 1 10 100 1 k 10 k 100 k
at T/K 2348 2562 2822 3141 3545 4072
Atomic properties
Crystal structure rhombohedral
Oxidation states 4,[1] 3, 1[2]
(mildly acidic oxide)
Electronegativity 2.04 (Pauling scale)
Ionization energies
(more)
1st: 800.6 kJ·mol−1
2nd: 2427.1 kJ·mol−1
3rd: 3659.7 kJ·mol−1
Atomic radius 85 pm
Atomic radius (calc.) 87 pm
Covalent radius 82 pm
Miscellaneous
Magnetic ordering nonmagnetic
Electrical resistivity (20 °C) 1.5×104Ω·m
Thermal conductivity (300 K) 27.4 W·m−1·K−1
Thermal expansion (25 °C) 5–7 µm·m−1·K−1
Speed of sound (thin rod) (20 °C) 16200 m/s
Bulk modulus (β form) 185 GPa
Mohs hardness 9.3
Vickers hardness 49000 MPa
CAS registry number 7440-42-8
Selected isotopes
Main article: Isotopes of boron
iso NA half-life DM DE (MeV) DP
10B 18.8%* 10B is stable with 5 neutrons
11B 81.2%* 11B is stable with 6 neutrons
*Boron-10 content may be as low as 19.1% and as
high as 20.3% in natural samples. Boron-11 is
the remainder in such cases.
References
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Boron (pronounced /ˈbɔərɒn/) is a chemical element with atomic number 5 and the chemical symbol B. Boron is a trivalent nonmetallic element which occurs abundantly in the evaporite ores borax and ulexite. Boron is never found as a free element in nature. Boron may mean: Boron, the chemical element Boron, Territoire de Belfort, the commune département in France Boron, California, the census-designated place in California Robert de Boron, the medieval poet Boron Oil Co. ... General Name, symbol, number beryllium, Be, 4 Chemical series alkaline earth metals Group, period, block 2, 2, s Appearance white-gray metallic Standard atomic weight 9. ... For other uses, see Carbon (disambiguation). ... Aluminum redirects here. ... Image File history File links B-TableImage. ... This is a standard display of the periodic table of the elements. ... An extended periodic table was suggested by Glenn T. Seaborg in 1969. ... This is a list of chemical elements, sorted by name and color coded according to type of element. ... Categories: Chemical elements ... sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex... Metalloid is a term used in chemistry when classifying the chemical elements. ... A group, also known as a family, is a vertical column in the periodic table of the chemical elements. ... In the periodic table of the elements, a period is a horizontal row of the table. ... A block of the periodic table of elements is a set of adjacent groups. ... The Boron group is periodic table group 13 (IUPAC style) in the periodic table. ... A period 2 element is one of the chemical elements in the second row (or period) of the periodic table of the elements. ... The p-block of the periodic table of elements consists of the last six groups. ... Color is an important part of the visual arts. ... Boron sample. ... The atomic mass (ma) is the mass of an atom at rest, most often expressed in unified atomic mass units. ... To help compare different orders of magnitude, the following list describes various mass levels between 10−36 kg and 1053 kg. ... Hydrogen = 1 List of Elements in Atomic Number Order. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... Electron atomic and molecular orbitals In atomic physics and quantum chemistry, the electron configuration is the arrangement of electrons in an atom, molecule, or other physical structure (, a crystal). ... For other uses, see Electron (disambiguation). ... Example of a sodium electron shell model An electron shell, also known as a main energy level, is a group of atomic orbitals with the same value of the principal quantum number n. ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... This box:      For other uses, see Solid (disambiguation). ... For other uses, see Density (disambiguation). ... For other uses, see Room temperature (disambiguation). ... Kilogram per cubic metre is the SI measure of density and is represented as kg/m³, where kg stands for kilogram and m³ stands for cubic metre. ... For other uses, see Density (disambiguation). ... The melting point of a solid is the temperature range at which it changes state from solid to liquid. ... The melting point of a solid is the temperature range at which it changes state from solid to liquid. ... For other uses, see Kelvin (disambiguation). ... For other uses, see Celsius (disambiguation). ... For other uses, see Fahrenheit (disambiguation). ... Italic text This article is about the boiling point of liquids. ... For other uses, see Kelvin (disambiguation). ... For other uses, see Celsius (disambiguation). ... For other uses, see Fahrenheit (disambiguation). ... Standard enthalpy change of fusion of period three. ... Kilojoule per mole are an SI derived unit of energy per amount of material, where energy is measured in units of 1000 joules, and the amount of material is measured in mole units. ... The heat of vaporization is a physical property of substances. ... Kilojoule per mole are an SI derived unit of energy per amount of material, where energy is measured in units of 1000 joules, and the amount of material is measured in mole units. ... Specific heat capacity, also known simply as specific heat, is the measure of the heat energy required to increase the temperature of a unit quantity of a substance by a certain temperature interval. ... Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. ... Enargite crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... Not to be confused with oxidation state. ... For other uses, see acid (disambiguation). ... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... The ionization energy (IE) of an atom or of a molecule is the energy required to strip it of an electron. ... These tables list the ionization energy in kJ/mol necessary to remove an electron from a neutral atom (first energy), respectively from a singly, doubly, etc. ... Kilojoule per mole are an SI derived unit of energy per amount of material, where energy is measured in units of 1000 joules, and the amount of material is measured in mole units. ... Atomic radius: Ionic radius Covalent radius Metallic radius Van der Waals radius edit Atomic radius, and more generally the size of an atom, is not a precisely defined physical quantity, nor is it constant in all circumstances. ... To help compare different orders of magnitude this page lists lengths between 10 pm and 100 pm (10-11 m and 10-12 m). ... One picometre is defined as 1x10-12 metres, in standard units. ... To help compare different orders of magnitude this page lists lengths between 10 pm and 100 pm (10-11 m and 10-12 m). ... Atomic radius: Ionic radius Covalent radius Metallic radius van der Waals radius edit The covalent radius, rcov, is a measure of the size of atom which forms part of a covalent bond. ... To help compare different orders of magnitude this page lists lengths between 10 pm and 100 pm (10-11 m and 10-12 m). ... For other senses of this word, see magnetism (disambiguation). ... // Headline text POOP!! Danny Hornsby (also known as Gnome) is a measure indicating how strongly a Gnome can opposes the flow of electric current. ... K value redirects here. ... During heat transfer, the energy that is stored in the intermolecular bonds between atoms changes. ... For other uses, see Speed of sound (disambiguation). ... Metre per second (U.S. spelling: meter per second) is an SI derived unit of both speed (scalar) and velocity (vector), defined by distance in metres divided by time in seconds. ... The bulk modulus (K) of a substance essentially measures the substances resistance to uniform compression. ... The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. ... A Vickers hardness tester The Vickers hardness test was developed in the early 1920s as an alternative method to measure the hardness of materials. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... Boron (B) Standard atomic mass: 10. ... For other uses, see Isotope (disambiguation). ... Natural abundance refers to the prevalence of different isotopes of an element as found in nature. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... In physics, the decay mode describes a particular way a particle decays. ... The decay energy is the energy released by a nuclear decay. ... The electronvolt (symbol eV) is a unit of energy. ... In nuclear physics, a decay product, also known as a daughter product, is a nuclide resulting from the radioactive decay of a parent or precursor nuclide. ... Stable isotopes are chemical isotopes that are not radioactive. ... This article or section does not adequately cite its references or sources. ... Stable isotopes are chemical isotopes that are not radioactive. ... This article or section does not adequately cite its references or sources. ... Recommended values for many properties of the elements, together with various references, are collected on these data pages. ... The periodic table of the chemical elements A chemical element, or element, is a type of atom that is distinguished by its atomic number; that is, by the number of protons in its nucleus. ... See also: List of elements by atomic number In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom. ... Together with the metals and metalloids, a nonmetal is one of three categories of chemical elements as distinguished by ionization and bonding properties. ... A sample of evaporite material Evaporites (IPA: ) are water-soluble, mineral sediments that result from the evaporation of bodies of surficial water. ... For other uses, see Ore (disambiguation). ... Borax from Persian burah. ... Ulexite (NaCaB5O9·8H2O) (hydrated sodium calcium borate hydroxide) is a mineral occurring in silky white rounded crystalline masses or in parallel fibers. ...


Several allotropes of boron exist; amorphous boron is a brown powder, though crystalline boron is black, hard (9.3 on Mohs' scale), and a weak conductor at room temperature. Elemental boron is used as a dopant in the semiconductor industry, while boron compounds play important roles as light structural materials, nontoxic insecticides and preservatives, and reagents for chemical synthesis. Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in structure. ... An amorphous solid is a solid in which there is no long-range order of the positions of the atoms. ... Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer. ... A dopant, also called doping agent and dope, is an impurity element added to a semiconductor lattice in low concentrations in order to alter the optical/electrical properties of the semiconductor. ...


Boron is an essential plant nutrient, although higher soil concentrations of boron may also be toxic to plants. As an ultratrace element, boron is necessary for the optimal health of rats and presumably other mammals, though its physiological role in animals is poorly understood. A nutrient is a substance used in an organisms metabolism which must be taken in from the environment. ... In biochemistry, an ultratrace element is a chemical element that normally comprises less than one microgram per gram of a given organism. ...

Contents

Characteristics

Brown amorphous boron is a product of certain chemical reactions. It contains boron atoms randomly bonded to each other without long range order.


Crystalline boron, a very hard black material with a high melting point, exists in many polymorphs. Two rhombohedral forms, α-boron and β-boron containing 12 and 106.7 atoms in the rhombohedral unit cell respectively, and 50-atom tetragonal boron are the three most characterised crystalline forms. Crystal (disambiguation) Insulin crystals A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ... Polymorphism in materials science is the ability of a solid material to exist in more than one form or crystal structure. ... In crystallography, the rhombohedral (or trigonal) crystal system is one of the 7 lattice point groups. ... In crystallography, the tetragonal crystal system is one of the 7 lattice point groups. ...


Optical characteristics of crystalline/elemental boron include the transmittance of infrared light. At standard temperatures, elemental boron is a poor electrical conductor, but is a good electrical conductor at high temperatures. For other uses, see Infrared (disambiguation). ... Not to be confused with electrical conductance, a measure of an objects or circuits ability to conduct an electric current between two points, which is dependent on the electrical conductivity and the geometric dimensions of the conducting object. ...


Chemically boron is electron-deficient, possessing a vacant p-orbital. It is an electrophile. Compounds of boron often behave as Lewis acids, readily bonding with electron-rich substances to compensate for boron's electron deficiency. The reactions of boron are dominated by such requirement for electrons. Also, boron is the least electronegative non-metal, meaning that it is usually oxidized (loses electrons) in reactions. For other uses, see Electron (disambiguation). ... The p-block of the periodic table of elements consists of the last six groups. ... In chemistry, an electrophile (literally electron-lover) is a reagent attracted to electrons that participates in a chemical reaction by accepting an electron pair in order to bond to a nucleophile. ... In chemistry, a Lewis acid can accept a pair of electrons and form a coordinate covalent bond, after the American chemist Gilbert Lewis. ... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ...


Boron is also similar to carbon with its capability to form stable covalently bonded molecular networks. Boron is also used for heat resistant alloys. Boron can form compounds whose formal oxidation state is not three eg B(II), in B2F4.[3] For other uses, see Carbon (disambiguation). ... Covalent redirects here. ...


Applications

10B and 11B NMR spectroscopy

both 10B (18.8 percent) and 11B (81.2 percent) possess nuclear spin; that of boron-10 has a value of 3 and that of boron-11, 3/2. These isotopes are, therefore, of use in nuclear magnetic resonance spectroscopy; and spectrometers specially adapted to detecting the boron-11 nucleus are available commercially. The boron-10 and boron-11 nuclei also cause splitting in the resonances of attached nuclei. In physics, spin refers to the angular momentum intrinsic to a body, as opposed to orbital angular momentum, which is generated by the motion of its center of mass about an external point. ... NMR redirects here. ... This article is about resonance in physics. ...


10B enriched boron

The 10B isotope is good at capturing thermal neutrons. Natural boron is about 20% 10B and 80%11B. The nuclear industry enriches natural boron to nearly pure 10B. The waste product, or depleted boron, is nearly pure 11B. 11B is a candidate as a fuel for aneutronic fusion and is used in the semiconductor industry. Enriched boron or 10B is used in both radiation shielding and in boron neutron capture therapy. In the later, a compound containing 10B is attached to a muscle near a tumor. The patient is then treated with a relatively low dose of thermal neutrons. This causes energetic and short range alpha radiation from the boron to bombard the tumor. This article does not cite its references or sources. ... This article is about applications of nuclear fission reactors as power sources. ... Aneutronic fusion is any form of fusion power where no more than 1% of the total energy released is carried by neutrons. ... Boron neutron capture therapy (BNCT) is an experimental form of radiotherapy that utilizes a neutron beam that interacts with boron injected to a patient. ...

Neutron cross section of boron (Black is 10B and blue is 11B)
Neutron cross section of boron (Black is 10B and blue is 11B)

In nuclear reactors, 10B is used for reactivity control and in emergency shutdown systems. It can serve either function in the form of borosilicate control rods or as boric acid. In pressurized water reactors, boric acid is added to the reactor coolant when the plant is shut down for refueling. It is then slowly filtered out over many months as fissile material is used up and the fuel becomes less reactive. Image File history File links Size of this preview: 800 × 547 pixelsFull resolution‎ (911 × 623 pixels, file size: 4 KB, MIME type: image/png) Other versions w:Image:Neutroncrosssectionboron. ... Image File history File links Size of this preview: 800 × 547 pixelsFull resolution‎ (911 × 623 pixels, file size: 4 KB, MIME type: image/png) Other versions w:Image:Neutroncrosssectionboron. ... Hello Please take a look at my one of a kind custom pyrex glass dildos made in upstate Ny all hand sculpted not machined. ... A control rod is a rod made of a chemical element capable of absorbing many neutrons without decaying themselves. ... Flash point Non-flammable. ... Pressurized water reactors (PWRs) (also VVER if of Russian design) are generation II nuclear power reactors that use ordinary water under high pressure as coolant and neutron moderator. ...


In future manned interplanetary spacecraft, 10B has a theoretical role as structural material (as boron fibers or BN nanotube material) which also would serve a special role in the radiation shield. One of the difficulties in dealing with cosmic rays which are mostly high energy protons, is that some secondary radiation from interaction of cosmic rays and spacecraft structural materials, is in the form of high energy spallation neutrons. Such neutrons can be moderated by materials high in light elements such as structural polyethylene, but the moderated neutrons continue to be a radiation hazard unless actively absorbed in a way which dumps the absorption energy in the shielding, far away from biological systems. Among light elements that absorb thermal neutrons, 6Li and 10B appear as potential spacecraft structural materials able to do double duty in this regard. Cosmic rays can loosely be defined as energetic particles originating outside of the Earth. ... In general, spallation is a process in which fragments of material are ejected from a body due to impact or stress. ...


11B depleted boron

Cosmic radiation produces secondary neutrons when it hits spacecraft structures. Neutrons produce fission in 10B if it is present in the spacecraft's semiconductors. This produces a gamma ray, an alpha particle, and a lithium ion. The resultant fission products may then dump charge into nearby chip structures, causing data loss (bit flipping, or single event upset). In radiation hardened semiconductor designs, one measure is to use depleted boron which is greatly enriched in 11B and contains almost no 10B. 11B is largely immune to radiation damage. Depleted boron is a by-product of the nuclear industry. Cosmic rays can loosely be defined as energetic particles originating outside of the Earth. ... For the generation of electrical power by fission, see Nuclear power plant. ... A semiconductor is a material that is an insulator at very low temperature, but which has a sizable electrical conductivity at room temperature. ... This article is about electromagnetic radiation. ... An alpha particle is deflected by a magnetic field Alpha radiation consists of helium-4 nuclei and is readily stopped by a sheet of paper. ... This article is about the chemical element. ... A single event upset (SEU) is a change of state, or voltage pulse caused when a high-energy particle strikes a sensitive node in a micro-electronic device, such as in a microprocessor, semiconductor memory, or power transistors. ... Microelectronics designed for environments with high levels of ionizing radiation have special design challenges. ... A semiconductor is a solid material that has electrical conductivity in between that of a conductor and that of an insulator; it can vary over that wide range either permanently or dynamically. ... This article is about applications of nuclear fission reactors as power sources. ...


11B is also a candidate as a fuel for aneutronic fusion. When struck by a proton of about 500 Kev, it produces three alpha particles and 8.7 Mev of energy. Most other fusion reactions involving hydrogen and helium produce penetrating neutron radiation. This induces long term radioactivity in reactor structures and weakens them, as well as endangering operating personnel. The alpha particles from 11B fusion can be turned directly into electric power and all radiation stops as soon as the reactor is turned off. Aneutronic fusion is any form of fusion power where no more than 1% of the total energy released is carried by neutrons. ...


Boron compounds

See also: Category:Boron compounds

The most economically important compounds of boron

Borax, (Na2B4O7·10H2O, sodium borate or sodium tetraborate) is an important boron compound. ... For sodium in the diet, see Salt. ... This article is about the chemical element and its most stable form, or dioxygen. ... This article is about the properties of water. ... Bundle of fiberglass Fiberglass (also called fibreglass and glass fibre) is material made from extremely fine fibers of glass. ... Sodium perborate (PBS), also called perboric acid or metaborate peroxyhydrate, is a white, odorless, water-soluble chemical compound with chemical formula NaBO3. ... In chemistry, to bleach something generally means to whiten it or oxidize it. ... This article is about the chemistry of hydrogen. ... This article is about the chemical element and its most stable form, or dioxygen. ... Flash point Non-flammable. ... Bundle of fiberglass Fiberglass (also called fibreglass and glass fibre) is material made from extremely fine fibers of glass. ... Flat panel displays encompass a growing number of technologies enabling video displays that are lighter and much thinner than traditional television and video displays using cathode ray tubes, usually less than 10 cm (4 inches) thick. ... Eye drops are saline-containing drops used as a vector to administer medication in the eye. ... Borax, (Na2B4O7·10H2O, sodium borate or sodium tetraborate) is an important boron compound. ... For sodium in the diet, see Salt. ... This article is about the chemical element and its most stable form, or dioxygen. ... This article is about the properties of water. ... Borax from Persian burah. ... Boron nitride is a binary chemical compound, consisting of equal proportions of boron and nitrogen, with formula BN. Structurally, it is isoelectronic to carbon and takes on similar physical forms: a hexagonal, graphite-like one, and a cubic, diamond-like one. ... For other uses, see Ammonia (disambiguation). ... Borazine is an inorganic compound composed of the elements boron, nitrogen and hydrogen. ...

Of the several hundred uses of boron compounds, especially notable uses

  • Boron is an essential plant micronutrient.
  • Because of its distinctive green flame, amorphous boron is used in pyrotechnic flares.
  • Boric acid is an important compound used in textile products.
  • Boric acid is also traditionally used as an insecticide, notably against ants, fleas, and cockroaches.
  • Borax is sometimes found in laundry detergent.
  • Boron filaments are high-strength, lightweight materials that are chiefly used for advanced aerospace structures as a component of composite materials, as well as limited production consumer and sporting goods such as golf clubs and fishing rods.
  • Boron is used as a melting point depressant in nickel-chromium braze alloys.
  • Boron slurry is used as an energetic material with very high energy density like rocket fuels and jet engines.
  • Boron compounds show promise in treating arthritis.
  • Due to its high neutron cross-section, boron is often used to control fission in nuclear reactors.
  • Sodium tetraborate pentahydrate - Used as a water clarifier in swimming pool water treatment

Micronutrients for plants: There are about eight nutrients essential to plant growth and health that are only present in very small quantities. ... A World War I-era parachute flare dropped from aircraft for illumination. ... Borax from Persian burah. ... Look up aerospace in Wiktionary, the free dictionary. ... A cloth of woven carbon fiber filaments, a common element in composite materials Composite materials (or composites for short) are engineered materials made from two or more constituent materials with significantly different physical or chemical properties and which remain separate and distinct on a macroscopic level within the finished structure. ... Some golf clubs. ... A fiberglass spinning rod and reel circa 1997. ... A slurry is in general a thick suspension of solids in a liquid and may be: Look up slurry in Wiktionary, the free dictionary. ... Energetic materials are a class of materials with high amount of stored chemical energy that can be released. ... Rocket fuel is a propellant that reacts with an oxidizing agent to produce thrust in a rocket. ... A Pratt and Whitney turbofan engine for the F-15 Eagle is tested at Robins Air Force Base, Georgia, USA. The tunnel behind the engine muffles noise and allows exhaust to escape. ... Arthritis (from Greek arthro-, joint + -itis, inflammation; plural: arthritides) is a group of conditions where there is damage caused to the joints of the body. ...

Hardest boron compounds

The hardest Boron compounds are created synthetically. Rhenium diboride (ReB2) and cubic (or beta)-Boron nitride can actually scratch diamond,but are still not as hard as diamond although Rhenium diboride surpasses diamond in certain directions.Rhenium diboride is nearly as hard as cubic boron nitride and boron suboxide, and much harder than Osmium diboride (which was the first step towards Rhenium diboride synthesis). Rhenium diboride (ReB2) is a synthetic superhard material of hardness comparable to diamond. ... Boron nitride is a binary chemical compound, consisting of equal proportions of boron and nitrogen, with formula BN. Structurally, it is isoelectronic to carbon and takes on similar physical forms: a hexagonal, graphite-like one, and a cubic, diamond-like one. ... Rhenium diboride (ReB2) is a synthetic superhard material of hardness comparable to diamond. ...


It is still a matter of research as to which Boron compound is the hardest:

  • Heterodiamond (called also BCN,it is supposed to be an improvement of Boron nitride, although it contains carbon).
  • cubic-Boron nitride (CBN or Borazon ,the latter being the commercial name.Discovered in 1957).
  • Rhenium diboride(as ReB2 synthesis requires considerably less pressure compared to cubic-Boron nitride, it is seen as an interesting economical alternative to CBN for the industry).

Each of these previously described materials, like all superhard materials with properties similar to diamond, do not have a unique hardness value but a hardness range, since hardness tests (ie. Knoop, Vickers, Rockwell, etc) depend on many conditions (direction, load...) according to whether the diamond used in the test will indent more or less deeply the given material. As a result, they all scratch each other as well as diamond under certain conditions.[citation needed] Heterodiamond is a new superhard material containing boron, carbon, and nitrogen (BCN). ... Boron nitride is a binary chemical compound, consisting of equal proportions of boron and nitrogen, with formula BN. Structurally, it is isoelectronic to carbon and takes on similar physical forms: a hexagonal, graphite-like one, and a cubic, diamond-like one. ... Rhenium diboride (ReB2) is a synthetic superhard material of hardness comparable to diamond. ... Boron nitride is a binary chemical compound, consisting of equal proportions of boron and nitrogen, with formula BN. Structurally, it is isoelectronic to carbon and takes on similar physical forms: a hexagonal, graphite-like one, and a cubic, diamond-like one. ... For many decades, engineers, scientists, and corporatiosn have seeked materials as hard as or harder than Diamonds in order to machine equipment along with create new matieral that is more attainable with similar phyiscal properties in order to create parts. ... The Knoop hardness test is a microhardness test - a test for mechanical hardness used particularly for very brittle materials or thin sheets, where only a small indentation may be made for testing purposes. ... Vickers was a famous name in British engineering that existed through many companies from 1828 until 2004. ... Rockwell can refer to: Rockwell International - a defense company in the United States Rockwell Automation - an industrial automation company that descended from Rockwell International Rockwell Collins - a communications and aviation electronics company that also descended from Rockwell International Willard Rockwell - businessman who helped shape and name what became Rockwell International...


These borides have been primarily developed as a substitute for diamond in coated tools (CVD or PVD diamond-like coated), as well as diamond powder coated blades, since diamond becomes soluble in iron and instable at certain given high temperatures thus reducing tool life. DC plasma (violet) enhances the growth of carbon nanotubes in this laboratory-scale PECVD apparatus. ... Physical vapor deposition (PVD) is a technique used to deposit thin films of various materials onto various surfaces (e. ...


Interestingly enough, Boron nitride in its hexagonal form (h-BN), is a very soft material (only 2 in Mohs hardness scale) compared to the cubic form ("Borazon"),h-BN being slightly more inert chemically than c-BN at very high temperatures, a feature extremely useful in advanced foundry and casting refractory applications (high end crucibles). Boron nitride is a binary chemical compound, consisting of equal proportions of boron and nitrogen, with formula BN. Structurally, it is isoelectronic to carbon and takes on similar physical forms: a hexagonal, graphite-like one, and a cubic, diamond-like one. ... Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer. ...


At a lesser degree, certain boronized (or borided) metals and alloys, through means of ion implantation or only ion beam deposition of Boron ions, show a spectacular increase in surface resistance and microhardness,thus having superficial characteristics similar to the corresponding borides. Laser alloying has also been successfully used for the same purpose. Atomic penetration of materials (aforementioned laser and implantation methods) are preferred over deposition methods (CVD deposition and PVD deposition) since the borides are formed "within" the metallic substrate (the ions penetrate literally the metal), relatively deep from the surface. Ion implantation is a materials engineering process by which ions of a material can be implanted into another solid, thereby changing the physical properties of the solid. ... Ion Beam Deposition is a process of applying materials to a target through the application of an ion beam. ... DC plasma (violet) enhances the growth of carbon nanotubes in this laboratory-scale PECVD apparatus. ... Physical vapor deposition (PVD) is a technique used to deposit thin films of various materials onto various surfaces (e. ...


Ultrahard fullerite , aggregated diamond nanorods and synthetic flawless diamond are still being considered as the undisputed hardest materials(they do not contain Boron). Scratch caused by ultrahard fullerite on diamond Ultrahard fullerite (C60) is a form of carbon found to be harder than diamond, and which can be used to create even harder materials, such as aggregated diamond nanorods. ... Aggregated diamond nanorods, or ADNRs, are an allotrope of carbon believed to be the hardest and least compressible known material, as measured by its isothermal bulk modulus; aggregated diamond nanorods have a modulus of 491 gigapascals (GPa), while a conventional diamond has a modulus of 442 GPa. ... This article is about the mineral. ...


History

Compounds of boron (Arabic Buraq from Persian Burah from Turkish Bor) have been known of for thousands of years. In early Egypt, mummification depended upon an ore known as natron, which contained borates as well as some other common salts. Borax glazes were used in China from CE 300, and boron compounds were used in glassmaking in ancient Rome. Arabic redirects here. ... Farsi redirects here. ... For other uses, see Mummy (disambiguation). ... Natron is a white, crystalline hygroscopic mineral salt, primarily a mixture of sodium bicarbonate (common baking soda) and sodium carbonate (soda ash) with small amounts of sodium chloride (table salt) and sodium sulfate. ... Composite body, painted, and glazed bottle. ... CE is an abbreviation which can have the following meanings: Capillary electrophoresis the CE mark is a stylized CE placed on products to signify conformance with European Union regulations. ...


The element was not isolated until 1808 by Sir Humphry Davy, Joseph Louis Gay-Lussac, and Louis Jacques Thénard, to about 50 percent purity, by the reduction of boric acid with sodium or magnesium. These men did not recognize the substance as an element. It was Jöns Jakob Berzelius in 1824 who identified boron as an element. The first pure boron was produced by the American chemist W. Weintraub in 1909, although this is disputed by some researchers.[4] Year 1808 (MDCCCVIII) was a leap year starting on Friday (link will display the full calendar) of the Gregorian calendar (or a leap year starting on Wednesday of the 12-day slower Julian calendar). ... Sir Humphry Davy, 1st Baronet FRS (17 December 1778 – 29 May 1829) was a British chemist and physicist. ... Joseph Louis Gay-Lussac. ... Louis Jacques Thénard. ... ed|other uses|reduction}} Illustration of a redox reaction Redox (shorthand for reduction/oxidation reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. ... Flash point Non-flammable. ... For sodium in the diet, see Salt. ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... Friherre Jöns Jakob Berzelius (August 20, 1779 – August 7, 1848) was a Swedish chemist. ...


Occurrence

Turkey and the United States are the world's largest producers of boron. Turkey has almost 72% of the world’s boron potential and boron reserves.[5] Boron does not appear in nature in elemental form but is found combined in borax, boric acid, colemanite, kernite, ulexite and borates. Boric acid is sometimes found in volcanic spring waters. Ulexite is a borate mineral that naturally has properties of fiber optics. Borax from Persian burah. ... Flash point Non-flammable. ... Colemanite Colemanite (Ca2B6O11·5H2O) is a borate mineral found in evaporite deposits. ... Kernite, also known as rasorite and hydrated sodium borate hydroxide (Na2B4O7·4H2O), is a colorless to white crystalline mineral that was formerly the chief source of borax. ... Ulexite (NaCaB5O9·8H2O) (hydrated sodium calcium borate hydroxide) is a mineral occurring in silky white rounded crystalline masses or in parallel fibers. ... Borates in chemistry are chemical compounds containing boron bonded to three oxygen atoms written as B(OR)3. ... Cleveland Volcano in the Aleutian Islands of Alaska photographed from the International Space Station For other uses, see Volcano (disambiguation). ... Borates in chemistry are chemical compounds containing boron bonded to three oxygen atoms written as B(OR)3. ... For other uses, see Mineral (disambiguation). ... Fiber Optic strands An optical fiber in American English or fibre in British English is a transparent thin fiber for transmitting light. ...

Borax crystals
Borax crystals

Economically important sources are from the ore rasorite (kernite) and tincal (borax ore) which are both found in the Mojave Desert of California, with borax being the most important source there. The largest borax deposits are found in Central and Western Turkey including the provinces of Eskişehir, Kütahya and Balıkesir. Image File history File linksMetadata Download high resolution version (1024x800, 113 KB) File links The following pages link to this file: Borax User:Aramgutang/Gallery Metadata This file contains additional information, probably added from the digital camera or scanner used to create or digitize it. ... Image File history File linksMetadata Download high resolution version (1024x800, 113 KB) File links The following pages link to this file: Borax User:Aramgutang/Gallery Metadata This file contains additional information, probably added from the digital camera or scanner used to create or digitize it. ... For other uses, see Ore (disambiguation). ... For the indigenous American tribe, see Mohave. ... This article is about the U.S. state. ... Borax from Persian burah. ... EskiÅŸehir (eskÄ“shehÄ“r, Latin: Dorylaeum, Greek: Δορύλαιον, Dorylaion) is a city in northwest Turkey and the capital of EskiÅŸehir Province. ... Kütahya is a city in western Turkey with 170,000 inhabitants (2004 estimate), lying on the Porsuk river, at 930 metres above sea level. ... Balıkesir is the capital city of Balıkesir Province in Turkey and has a population of 215,436. ...


See also: Borate minerals.


Commercial production of the free element

Pure elemental boron is not easy to prepare. The earliest methods used involve reduction of boric oxide with metals such as magnesium or aluminium. However the product is almost always contaminated with metal borides. (The reaction is quite spectacular though.) Pure boron can be prepared by reducing volatile boron halogenides with hydrogen at high temperatures. The highly pure boron, for the use in semiconductor industry, is produced by the decomposition of diborane at high temperatures and then further purified with the Czochralski process. Boron oxide is a colourless or white solid, also known as diboron trioxide, formula B2O3. ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... Aluminum redirects here. ... The boride ion is B3- (a boron atom plus three electrons). ... This article is about the chemistry of hydrogen. ... Diborane is a colorless gas at room temperature with a repulsive, sweet odor. ... The Czochralski process is a method of crystal growth used to obtain single crystals of semiconductors (e. ...


Market trend

Estimated global consumption of boron rose to a record 1.8 million tonnes of B2O3 in 2005 following a period of strong growth in demand from Asia, Europe and North America. Boron mining and refining capacities are considered to be adequate to meet expected levels of growth through the next decade. The form in which boron is consumed has changed in recent years. The use of beneficiated ores like colemanite has declined following concerns over arsenic content. Consumers have moved towards the use of refined borates or boric acid that have a lower pollutant content. The average cost of crystalline boron is $5/g.[6] Colemanite Colemanite (Ca2B6O11·5H2O) is a borate mineral found in evaporite deposits. ... General Name, Symbol, Number arsenic, As, 33 Chemical series metalloids Group, Period, Block 15, 4, p Appearance metallic gray Standard atomic weight 74. ...


Increasing demand for boric acid has led a number of producers to invest in additional capacity. Eti Mine opened a new 100,000 tonnes per year capacity boric acid plant at Emet in 2003. Rio Tinto increased the capacity of its Boron plant from 260,000 tonnes per year in 2003 to 310,000 tonnes per year by May 2005, with plans to grow this to 366,000 tonnes per year in 2006. Rio Tinto may refer to: Rio Tinto (Paraíba), in Paraíba State, Brazil. ...


Chinese boron producers have been unable to meet rapidly growing demand for high quality borates. This has led to imports of disodium tetraborate growing by a hundredfold between 2000 and 2005 and boric acid imports increasing by 28% per year over the same period.


The rise in global demand has been driven by high rates of growth in fiberglass and borosilicate production. A rapid increase in the manufacture of reinforcement-grade fiberglass in Asia with a consequent increase in demand for borates has offset the development of boron-free reinforcement-grade fiberglass in Europe and the USA. The recent rises in energy prices can be expected to lead to greater use of insulation-grade fiberglass, with consequent growth in the use of boron. Bundle of fiberglass Fiberglass (also called fibreglass and glass fibre) is material made from extremely fine fibers of glass. ...


Roskill Consulting Group forecasts that world demand for boron will grow by 3.4% per year to reach 21 million tonnes by 2010. The highest growth in demand is expected to be in Asia where demand could rise by an average 5.7% per year.[7]


Boron in biology

A boron-containing natural antibiotic, boromycin, isolated from streptomyces, is known.[8][9] Staphylococcus aureus - Antibiotics test plate. ... The boron-containing polyether-macrolide antibiotic, boromycin, was isolated as a potent anti-human immunodeficiency virus (HIV) antibiotic from a fermentation broth of Streptomyces sp. ... Streptomyces is a genus of Actinobacteria. ...


Boron is an essential plant nutrient, required primarily for maintaining the integrity of cell walls. Conversely, high soil concentrations of > 1.0 ppm can cause marginal and tip necrosis in leaves as well as poor overall growth performance. Levels as low as 0.8 ppm can cause these same symptoms to appear in plants particularly sensitive to boron in the soil. Nearly all plants, even those somewhat tolerant of boron in the soil, will show at least some symptoms of boron toxicity when boron in the soil is greater than 1.8 ppm. When boron in the soil exceeds 2.0 ppm, few plants will perform well. Plants sensitive to boron in the soil may not survive. When boron levels in plant tissue exceed 200 ppm symptoms of boron toxicity are likely to appear. A nutrient is a substance used in an organisms metabolism which must be taken in from the environment. ...


As an ultratrace element, boron is necessary for the optimal health of rats, although it is necessary in such small amounts that ultrapurified foods and dust filtration of air is necessary to show the effects of boron deficiency, which manefest as poor coat/hair quality. Presumably, boron is necessary to other mammals. No deficiency syndrome in humans has been described. Small amounts of boron occur widely in the diet, and the amounts needed in the diet would, by analogy with rodent studies, be very small. The exact physiological role of boron in the animal kingdom is poorly understood. In biochemistry, an ultratrace element is a chemical element that normally comprises less than one microgram per gram of a given organism. ...


Boron occurs in all foods produced from plants. Since 1989 its nutritional value has been argued. It is thought that boron plays several biochemical roles in animals, including humans.[10] The U.S. Department of agriculture conducted an experiment in which postmenopausal women took 3 mg of boron a day. The results showed that supplemental boron reduced excretion of calcium by 44%, and activated estrogen and vitamin D. However, whether these effects were conventionally nutritional, or medicinal, could not be determined.


The US National Institute of Health quotes this source: The National Institutes of Health is an institution of the United States government which focuses on medical research. ...

Total daily boron intake in normal human diets ranges from 2.1–4.3 mg boron/kg body weight (bw)/day. "Total boron". Zook EG and Lehman J. J. Assoc. Off Agric. Chem. 48: 850-5 (1965).

In nutrition, the diet is the sum of food consumed by a person or other organism. ...

Analytical quantification

For determination of boron content in food or materials the colorimetric curcumin method is used. Boron has to be transferred to boric acid or borates and on reaction with curcumin in acidic solution a red colored boron-chelate complex, rosocyanine, is formed. This article or section is not written in the formal tone expected of an encyclopedia article. ... Flash point Non-flammable. ... Borates in chemistry are chemical compounds containing boron bonded to three oxygen atoms written as B(OR)3. ... Curcumin is the active ingredient of the Indian curry spice turmeric. ... Chelation (from Greek, claw like) describes the reversible binding of an organic ligand, the chelator or chelating agent, to a metal ion, forming a metal complex, the chelate. ... Rosocyanine and Rubrocurcumin are two red colored materials, which are formed by the reaction between curcumin and borates. ...


Isotopes

Boron has two naturally-occurring and stable isotopes, 11B (80.1%) and 10B (19.9%). The mass difference results in a wide range of δ11B values in natural waters, ranging from -16 to +59. There are 13 known isotopes of boron, the shortest-lived isotope is 7B which decays through proton emission and alpha decay. It has a half-life of 3.26500x10-22 s. Isotopic fractionation of boron is controlled by the exchange reactions of the boron species B(OH)3 and B(OH)4. Boron isotopes are also fractionated during mineral crystallization, during H2O phase changes in hydrothermal systems, and during hydrothermal alteration of rock. The latter effect species preferential removal of the 10B(OH)4 ion onto clays results in solutions enriched in 11B(OH)3 may be responsible for the large 11B enrichment in seawater relative to both oceanic crust and continental crust; this difference may act as an isotopic signature. For other uses, see Isotope (disambiguation). ... Proton emission (also known as proton radioactivity) is a type of radioactive decay in which a proton is ejected from a nucleus. ... Alpha decay Alpha decay is a type of radioactive decay in which an atom emits an alpha particle (two protons and two neutrons bound together into a particle identical to a helium nucleus) and transforms (or decays) into an atom with a mass number 4 less and atomic number 2... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... This article is about the unit of time. ... This article is about the chemical element and its most stable form, or dioxygen. ... This article is about the chemistry of hydrogen. ... Hydrothermal circulation in the oceans is the passage of the water through mid-ocean Ridge (MOR) systems. ... This article is about the geological substance. ... This article is about the electrically charged particle. ... Animated map exhibiting the worlds oceanic waters. ... Animated, colour-coded map showing the various continents. ... An isotopic signature (also isotopic fingerprint) is a ratio of stable or unstable isotopes of particular elements found in an investigated material. ...


The exotic 17B exhibits a Nuclear halo.[citation needed] In nuclear physics, an atomic nucleus is said to be a halo if its radius is appreciably larger than that predicted by the liquid drop model, wherein the nucleus is considered to be a sphere of constant density. ...


Precautions

Elemental boron is nontoxic and common boron compounds such as borates and boric acid have low toxicity (approximately similar to table salt with the lethal dose being 2 to 3 grams per kg) and therefore do not require special precautions while handling. Some of the more exotic boron hydrogen compounds, however, are toxic as well as highly flammable and do require special handling care. Flash point Non-flammable. ... In chemistry a borane is a chemical compound of boron and hydrogen. ... Flammable or Flammability refers to the ease at which a substance will ignite, causing fire or combustion. ...


See also

Boron (B) deficiency is a rare disorder affecting plants growing above a granite bedrock, which is low in boron. ... The general structure of a boronic acid, where R is a substituent. ... In organic chemistry, the Suzuki reaction couples the following two things: Organoborane, in a basic solution An aryl, benzyl, or vinyl halide An example of a Suzuki reaction pathway. ... Wikibooks has more about this subject: Hydroboration (Organic chemistry) In organic chemistry, the hydroboration-oxidation reaction is a two-step organic chemical reaction that converts an alkene into a neutral alcohol by the net addition of water across the double bond. ...

References

  1. ^ W.T.M.L. Fernando, L.C. O'Brien, P.F. Bernath. Fourier Transform Spectroscopy: B4Σ−X4Σ. University of Arizona, Tucson. Retrieved on 2007-12-10.
  2. ^ K.Q. Zhang, B.Guo, V. Braun, M. Dulick, P.F. Bernath. Infrared Emission Spectroscopy of BF and AIF. Retrieved on 2007-12-10.
  3. ^ Compound Descriptions: B2F4. Landol Börnstein Substance/Property Index. Retrieved on 2007-12-10.
  4. ^ "" (1970). Z. Angew. Phys. 29: 277. 
  5. ^ Developments in the Ecomomic Sector (of Turkey). Turkish government. Retrieved on 2007-12-21.
  6. ^ Rare-Earth Magnets - Boron Properties
  7. ^ http://www.roskill.com/reports/prePublication/prepubboron
  8. ^ R. Hütter, W. Keller-Schien, F. Knüsel, V. Prelog , G. C. Rodgers jr., P. Suter, G. Vogel, W. Voser, H. Zähner (1967). "Stoffwechselprodukte von Mikroorganismen. 57. Mitteilung. Boromycin". Helv. Chim. Acta. 50: 1533–1539. doi:10.1002/hlca.19670500612. 
  9. ^ J. D. Dunitz, D. M. Hawley, D. Miklo, D. N. J. White, Yu. Berlin, R. Marui, V. Prelog (1971). "Structure of boromycin". Helv. Chim. Acta. 54: 1709–1713. doi:10.1002/hlca.19710540624. 
  10. ^ Boron

Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 344th day of the year (345th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 344th day of the year (345th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 344th day of the year (345th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 355th day of the year (356th in leap years) in the Gregorian calendar. ... Vladimir Prelog (July 23, 1906 – January 7, 1998) was a renowned Bosnian - Croatian chemist who worked in Prague, Zagreb and Zurich and who won the Nobel Prize in chemistry in 1975. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Vladimir Prelog (July 23, 1906 – January 7, 1998) was a renowned Bosnian - Croatian chemist who worked in Prague, Zagreb and Zurich and who won the Nobel Prize in chemistry in 1975. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

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Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 151 languages. ... The International Programme on Chemical Safety (IPCS) is a collaboration between three United Nations bodies—the World Health Organization, the International Labour Organization and the United Nations Environment Programme. ... The Periodic Table redirects here. ... This article is about the chemistry of hydrogen. ... General Name, symbol, number helium, He, 2 Chemical series noble gases Group, period, block 18, 1, s Appearance colorless Standard atomic weight 4. ... This article is about the chemical element. ... General Name, symbol, number beryllium, Be, 4 Chemical series alkaline earth metals Group, period, block 2, 2, s Appearance white-gray metallic Standard atomic weight 9. ... For other uses, see Carbon (disambiguation). ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... This article is about the chemical element and its most stable form, or dioxygen. ... Distinguished from fluorene and fluorone. ... For other uses, see Neon (disambiguation). ... For sodium in the diet, see Salt. ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... Aluminum redirects here. ... Not to be confused with Silicone. ... General Name, symbol, number phosphorus, P, 15 Chemical series nonmetals Group, period, block 15, 3, p Appearance waxy white/ red/ black/ colorless Standard atomic weight 30. ... This article is about the chemical element. ... General Name, symbol, number chlorine, Cl, 17 Chemical series nonmetals Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... General Name, symbol, number argon, Ar, 18 Chemical series noble gases Group, period, block 18, 3, p Appearance colorless Standard atomic weight 39. ... General Name, symbol, number potassium, K, 19 Chemical series alkali metals Group, period, block 1, 4, s Appearance silvery white Standard atomic weight 39. ... For other uses, see Calcium (disambiguation). ... General Name, symbol, number scandium, Sc, 21 Chemical series transition metals Group, period, block 3, 4, d Appearance silvery white Standard atomic weight 44. ... General Name, symbol, number titanium, Ti, 22 Chemical series transition metals Group, period, block 4, 4, d Appearance silvery grey-white metallic Standard atomic weight 47. ... General Name, symbol, number vanadium, V, 23 Chemical series transition metals Group, period, block 5, 4, d Appearance silver-grey metal Standard atomic weight 50. ... REDIRECT [[ Insert text]]EWWWWWWWWWWWWW YO General Name, symbol, number chromium, Cr, 24 Chemical series transition metals Group, period, block 6, 4, d Appearance silvery metallic Standard atomic weight 51. ... General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ... General Name, symbol, number iron, Fe, 26 Chemical series transition metals Group, period, block 8, 4, d Appearance lustrous metallic with a grayish tinge Standard atomic weight 55. ... For other uses, see Cobalt (disambiguation). ... For other uses, see Nickel (disambiguation). ... For other uses, see Copper (disambiguation). ... General Name, symbol, number zinc, Zn, 30 Chemical series transition metals Group, period, block 12, 4, d Appearance bluish pale gray Standard atomic weight 65. ... Not to be confused with Galium. ... General Name, Symbol, Number germanium, Ge, 32 Chemical series metalloids Group, Period, Block 14, 4, p Appearance grayish white Standard atomic weight 72. ... General Name, Symbol, Number arsenic, As, 33 Chemical series metalloids Group, Period, Block 15, 4, p Appearance metallic gray Standard atomic weight 74. ... For other uses, see Selenium (disambiguation). ... Bromo redirects here. ... For other uses, see Krypton (disambiguation). ... General Name, Symbol, Number rubidium, Rb, 37 Chemical series alkali metals Group, Period, Block 1, 5, s Appearance grey white Standard atomic weight 85. ... General Name, Symbol, Number strontium, Sr, 38 Chemical series alkaline earth metals Group, Period, Block 2, 5, s Appearance silvery white metallic Standard atomic weight 87. ... General Name, Symbol, Number yttrium, Y, 39 Chemical series transition metals Group, Period, Block 3, 5, d Appearance silvery white Standard atomic weight 88. ... General Name, Symbol, Number zirconium, Zr, 40 Chemical series transition metals Group, Period, Block 4, 5, d Appearance silvery white Standard atomic weight 91. ... General Name, Symbol, Number niobium, Nb, 41 Chemical series transition metals Group, Period, Block 5, 5, d Appearance gray metallic Standard atomic weight 92. ... General Name, Symbol, Number molybdenum, Mo, 42 Chemical series transition metals Group, Period, Block 6, 5, d Appearance gray metallic Standard atomic weight 95. ... General Name, Symbol, Number technetium, Tc, 43 Chemical series transition metals Group, Period, Block 7, 5, d Appearance silvery gray metal Standard atomic weight [98](0) g·mol−1 Electron configuration [Kr] 4d5 5s2 Electrons per shell 2, 8, 18, 13, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number Ruthenium, Ru, 44 Chemical series transition metals Group, Period, Block 8, 5, d Appearance silvery white metallic Standard atomic weight 101. ... General Name, Symbol, Number rhodium, Rh, 45 Chemical series transition metals Group, Period, Block 9, 5, d Appearance silvery white metallic Standard atomic weight 102. ... For other uses, see Palladium (disambiguation). ... This article is about the chemical element. ... General Name, Symbol, Number cadmium, Cd, 48 Chemical series transition metals Group, Period, Block 12, 5, d Appearance silvery gray metallic Standard atomic weight 112. ... General Name, Symbol, Number indium, In, 49 Chemical series poor metals Group, Period, Block 13, 5, p Appearance silvery lustrous gray Standard atomic weight 114. ... This article is about the metallic chemical element. ... This article is about the element. ... General Name, Symbol, Number tellurium, Te, 52 Chemical series metalloids Group, Period, Block 16, 5, p Appearance silvery lustrous gray Standard atomic weight 127. ... For other uses, see Iodine (disambiguation). ... General Name, Symbol, Number xenon, Xe, 54 Chemical series noble gases Group, Period, Block 18, 5, p Appearance colorless Standard atomic weight 131. ... General Name, Symbol, Number caesium, Cs, 55 Chemical series alkali metals Group, Period, Block 1, 6, s Appearance silvery gold Standard atomic weight 132. ... For other uses, see Barium (disambiguation). ... General Name, Symbol, Number lanthanum, La, 57 Chemical series lanthanides Group, Period, Block 3, 6, f Appearance silvery white Atomic mass 138. ... General Name, Symbol, Number cerium, Ce, 58 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Standard atomic weight 140. ... General Name, Symbol, Number praseodymium, Pr, 59 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance grayish white Standard atomic weight 140. ... General Name, Symbol, Number neodymium, Nd, 60 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white, yellowish tinge Standard atomic weight 144. ... General Name, Symbol, Number promethium, Pm, 61 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance metallic Atomic mass [145](0) g/mol Electron configuration [Xe] 4f5 6s2 Electrons per shell 2, 8, 18, 23, 8, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number samarium, Sm, 62 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Atomic mass 150. ... General Name, Symbol, Number gadolinium, Gd, 64 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Standard atomic weight 157. ... General Name, Symbol, Number terbium, Tb, 65 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Atomic mass 158. ... General Name, Symbol, Number dysprosium, Dy, 66 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Standard atomic weight 162. ... General Name, Symbol, Number holmium, Ho, 67 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Atomic mass 164. ... General Name, Symbol, Number erbium, Er, 68 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Standard atomic weight 167. ... General Name, Symbol, Number thulium, Tm, 69 Chemical series lanthanides Group, Period, Block ?, 6, f Appearance silvery gray Atomic mass 168. ... Yb redirects here; for the unit of information see Yottabit General Name, Symbol, Number ytterbium, Yb, 70 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Standard atomic weight 173. ... General Name, Symbol, Number lutetium, Lu, 71 Chemical series lanthanides Group, Period, Block n/a, 6, d Appearance silvery white Standard atomic weight 174. ... General Name, Symbol, Number hafnium, Hf, 72 Chemical series transition metals Group, Period, Block 4, 6, d Appearance grey steel Standard atomic weight 178. ... General Name, Symbol, Number tantalum, Ta, 73 Chemical series transition metals Group, Period, Block 5, 6, d Appearance gray blue Standard atomic weight 180. ... For other uses, see Tungsten (disambiguation). ... General Name, Symbol, Number rhenium, Re, 75 Chemical series transition metals Group, Period, Block 7, 6, d Appearance grayish white Standard atomic weight 186. ... General Name, Symbol, Number osmium, Os, 76 Chemical series transition metals Group, Period, Block 8, 6, d Appearance silvery, blue cast Standard atomic weight 190. ... This article is about the chemical element. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... GOLD refers to one of the following: GOLD (IEEE) is an IEEE program designed to garner more student members at the university level (Graduates of the Last Decade). ... This article is about the element. ... General Name, Symbol, Number thallium, Tl, 81 Chemical series poor metals Group, Period, Block 13, 6, p Appearance silvery white Standard atomic weight 204. ... General Name, Symbol, Number lead, Pb, 82 Chemical series Post-transition metals or poor metals Group, Period, Block 14, 6, p Appearance bluish gray Standard atomic weight 207. ... General Name, Symbol, Number bismuth, Bi, 83 Chemical series poor metals Group, Period, Block 15, 6, p Appearance lustrous pink Standard atomic weight 208. ... General Name, Symbol, Number polonium, Po, 84 Chemical series metalloids Group, Period, Block 16, 6, p Appearance silvery Standard atomic weight (209) g·mol−1 Electron configuration [Xe] 6s2 4f14 5d10 6p4 Electrons per shell 2, 8, 18, 32, 18, 6 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number astatine, At, 85 Chemical series halogens Group, Period, Block 17, 6, p Appearance metallic (presumed) Standard atomic weight (210) g·mol−1 Electron configuration [Xe] 4f14 5d10 6s2 6p5 Electrons per shell 2, 8, 18, 32, 18, 7 Physical properties Phase solid Melting point 575 K... For other uses, see Radon (disambiguation). ... General Name, Symbol, Number francium, Fr, 87 Chemical series alkali metals Group, Period, Block 1, 7, s Appearance metallic Standard atomic weight (223) g·mol−1 Electron configuration [Rn] 7s1 Electrons per shell 2, 8, 18, 32, 18, 8, 1 Physical properties Phase  ? solid Density (near r. ... For other uses, see Radium (disambiguation). ... General Name, Symbol, Number actinium, Ac, 89 Chemical series actinides Group, Period, Block 3, 7, f Appearance silvery Standard atomic weight (227) g·mol−1 Electron configuration [Rn] 6d1 7s2 Electrons per shell 2, 8, 18, 32, 18, 9, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number thorium, Th, 90 Chemical series Actinides Group, Period, Block n/a, 7, f Appearance silvery white Standard atomic weight 232. ... General Name, Symbol, Number protactinium, Pa, 91 Chemical series actinides Group, Period, Block n/a, 7, f Appearance bright, silvery metallic luster Standard atomic weight 231. ... This article is about the chemical element. ... General Name, Symbol, Number neptunium, Np, 93 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery metallic Standard atomic weight (237) g·mol−1 Electron configuration [Rn] 5f4 6d1 7s2 Electrons per shell 2, 8, 18, 32, 22, 9, 2 Physical properties Phase solid Density (near r. ... This article is about the radioactive element. ... General Name, Symbol, Number americium, Am, 95 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white sometimes yellow Standard atomic weight (243) g·mol−1 Electron configuration [Rn] 5f7 7s2 Electrons per shell 2, 8, 18, 32, 25, 8, 2 Physical properties Phase solid Density (near... General Name, Symbol, Number curium, Cm, 96 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery Atomic mass (247) g/mol Electron configuration [Rn] 5f7 6d1 7s2 Electrons per shell 2, 8, 18, 32, 25, 9, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number berkelium, Bk, 97 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (247) g·mol−1 Electron configuration [Rn] 5f9 7s2 Electrons per shell 2, 8, 18, 32, 27, 8, 2 Physical properties Phase solid... General Name, Symbol, Number californium, Cf, 98 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (251) g·mol−1 Electron configuration [Rn] 5f10 7s2 Electrons per shell 2, 8, 18, 32, 28, 8, 2 Physical properties Phase solid... General Name, Symbol, Number einsteinium, Es, 99 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Standard atomic weight (252) g·mol−1 Electron configuration [Rn] 5f11 7s2 Electrons per shell 2, 8, 18, 32, 29, 8, 2 Physical properties Phase... General Name, Symbol, Number fermium, Fm, 100 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (257) g·mol−1 Electron configuration [Rn] 5f12 7s2 Electrons per shell 2, 8, 18, 32, 30, 8, 2 Physical properties Phase solid... General Name, Symbol, Number mendelevium, Md, 101 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (258) g·mol−1 Electron configuration [Rn] 5f13 7s2 Electrons per shell 2, 8, 18, 32, 31, 8, 2 Physical properties Phase solid... General Name, Symbol, Number nobelium, No, 102 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (259) g/mol Electron configuration [Rn] 5f14 7s2 Electrons per shell 2, 8, 18, 32, 32, 8, 2 Physical properties Phase solid Melting... General Name, Symbol, Number lawrencium, Lr, 103 Chemical series transition metals Group, Period, Block n/a, 7, d Appearance unknown, probably silvery white or metallic gray Standard atomic weight [262] g·mol−1 Electron configuration [Rn] 5f14 6d1 7s2 Electrons per shell 2, 8, 18, 32, 32, 9, 2 Physical... General Name, Symbol, Number rutherfordium, Rf, 104 Chemical series transition metals Group, Period, Block 4, 7, d Standard atomic weight (265) g·mol−1 Electron configuration probably [Rn] 5f14 6d2 7s2 Electrons per shell 2, 8, 18, 32, 32, 10, 2 Physical properties Phase presumably a solid Density (near r. ... General Name, Symbol, Number dubnium, Db, 105 Chemical series transition metals Group, Period, Block 5, 7, d Appearance unknown, probably silvery white or metallic gray Atomic mass (262) g/mol Electron configuration perhaps [Rn] 5f14 6d3 7s2 (guess based on tantalum) Electrons per shell 2, 8, 18, 32, 32, 11... General Name, Symbol, Number seaborgium, Sg, 106 Chemical series transition metals Group, Period, Block 6, 7, d Appearance unknown, probably silvery white or metallic gray Atomic mass (266) g/mol Electron configuration perhaps [Rn] 5f14 6d4 7s2 (guess based on tungsten) Electrons per shell 2, 8, 18, 32, 32, 12... General Name, Symbol, Number bohrium, Bh, 107 Chemical series transition metals Group, Period, Block 7, 7, d Appearance unknown, probably silvery white or metallic gray Atomic mass (264) g/mol Electron configuration perhaps [Rn] 5f14 6d5 7s2 (guess based on rhenium) Electrons per shell 2, 8, 18, 32, 32, 13... General Name, Symbol, Number hassium, Hs, 108 Chemical series transition metals Group, Period, Block 8, 7, d Appearance unknown, probably silvery white or metallic gray Atomic mass (269) g/mol Electron configuration perhaps [Rn] 5f14 6d6 7s2 (guess based on osmium) Electrons per shell 2, 8, 18, 32, 32, 14... General Name, Symbol, Number meitnerium, Mt, 109 Chemical series transition metals Group, Period, Block 9, 7, d Appearance unknown, probably silvery white or metallic gray Atomic mass (268) g·mol−1 Electron configuration perhaps [Rn] 5f14 6d7 7s2 (guess based on iridium) Electrons per shell 2, 8, 18, 32, 32... General Name, Symbol, Number darmstadtium, Ds, 110 Chemical series transition metals Group, Period, Block 10, 7, d Appearance unknown, probably silvery white or metallic gray Atomic mass (281) g/mol Electron configuration perhaps [Rn] 5f14 6d9 7s1 (guess based on platinum) Electrons per shell 2, 8, 18, 32, 32, 17... General Name, Symbol, Number roentgenium, Rg, 111 Chemical series transition metals Group, Period, Block 11, 7, d Appearance unknown, probably yellow or orange metallic Atomic mass (284) g/mol Electron configuration perhaps [Rn] 5f14 6d10 7s1 (guess based on gold) Electrons per shell 2, 8, 18, 32, 32, 18, 1... General Name, Symbol, Number ununbium, Uub, 112 Chemical series transition metals Group, Period, Block 12, 7, d Appearance unknown, probably silvery white or metallic gray liquid Atomic mass (285) g/mol Electron configuration perhaps [Rn] 5f14 6d10 7s2 (guess based on mercury) Electrons per shell 2, 8, 18, 32, 32... General Name, Symbol, Number ununtrium, Uut, 113 Chemical series presumably poor metals Group, Period, Block 13, 7, p Appearance unknown, probably silvery white or metallic gray Atomic mass (284) g/mol Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p1 (guess based on thallium) Electrons per shell 2, 8, 18, 32... General Name, Symbol, Number ununquadium, Uuq, 114 Chemical series presumably poor metals Group, Period, Block 14, 7, p Appearance unknown, probably silvery white or metallic gray Standard atomic weight [289] g·mol−1 Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p2 (guess based on lead) Electrons per shell 2, 8... General Name, Symbol, Number ununpentium, Uup, 115 Group, Period, Block 15, 7, p Atomic mass (299) g·mol−1 Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p3 (guess based on bismuth) Electrons per shell 2, 8, 18, 32, 32, 18, 5 CAS registry number 54085-64-2 Selected isotopes References... General Name, Symbol, Number ununhexium, Uuh, 116 Chemical series presumably poor metals Group, Period, Block 16, 7, p Appearance unknown, probably silvery white or metallic gray Atomic mass (302) g/mol Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p4 (guess based on polonium) Electrons per shell 2, 8, 18, 32... General Name, Symbol, Number ununseptium, Uus, 117 Chemical series presumably halogens Group, Period, Block 17, 7, p Appearance unknown, probably dark metallic Standard atomic weight predicted, (310) g·mol−1 Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p5 (guess based on astatine) Electrons per shell 2, 8, 18, 32, 32... General Name, Symbol, Number ununoctium, Uuo, 118 Chemical series noble gases Group, Period, Block 18, 7, p Appearance unknown, probably colorless Atomic mass predicted, (314) g/mol Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p6 (guess based on radon) Electrons per shell 2, 8, 18, 32, 32, 18, 8 Phase... The alkali metals are a series of elements comprising Group 1 (IUPAC style) of the periodic table: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). ... The alkaline earth metals are a series of elements comprising Group 2 (IUPAC style) of the periodic table: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra). ... The lanthanide (or lanthanoid) series comprises the 15 elements with atomic numbers 57 through 71, from lanthanum to lutetium[1]. All lanthanides are f-block elements, corresponding to the filling of the 4f electron shell, except for lutetium which is a d-block lanthanide. ... The actinide series encompasses the 14 chemical elements that lie between actinium and nobelium on the periodic table with atomic numbers 89 - 102 inclusive. ... This article is in need of attention. ... This article is about metallic materials. ... Metalloid is a term used in chemistry when classifying the chemical elements. ... Together with the metals and metalloids, a nonmetal is one of three categories of chemical elements as distinguished by ionization and bonding properties. ... This article is about the chemical series. ... This article is about the chemical series. ...

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MedlinePlus Herbs and Supplements: Boron (1750 words)
Boron should be avoided in patients who have a history of reactions to boron, boric acid, borax, citrate, aspartate, or glycinate.
Boron is potentially toxic, although humans tend to rapidly excrete it and therefore boron does not usually accumulate in high levels.
Boron may be associated with reduced blood levels of calcitonin, insulin, or phosphorus and with increased levels of vitamin D2, calcium, copper, magnesium, or thyroxine.
Boron (3834 words)
Boron is one of the simplest of atoms.
The density of crystalline boron is 2.34 g/cc, of amorphous boron, 2.37.
Boron gives a blue-green flame, and the brown amorphous form is often used in pyrotechical devices for this purpose.
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