Boron nitride
Identifiers
CAS number	[10043-11-5]
EINECS number	233-136-6
Properties
Molecular formula	BN
Molar mass	24. CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to The EINECS number (for European Inventory of Existing Chemical Substances) is a registry number given to each Chemical substance commercially available in the A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Molar mass, symbol M, is the Mass of one mole of a substance ( Chemical element or Chemical compound) 818 g mol−1
Appearance	white solid
Density	2. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 18 g cm−3
Melting point	2700 °C (sublimes)
Solubility in water	insoluble
Structure
Crystal structure	hexagonal or tetrahedral-cubic
Thermochemistry
Std enthalpy of formation ΔfHo298	476. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. Water is a common Chemical substance that is essential for the survival of all known forms of Life. In Mineralogy and Crystallography, a crystal structure is a unique arrangement of Atoms in a Crystal. Regular hexagon The internal Angles of a regular hexagon (one where all sides and all angles are equal are all 120 ° and the hexagon has 720 degrees A tetrahedron (plural tetrahedra) is a Polyhedron composed of four triangular faces three of which meet at each vertex. The cubic crystal system (or isometric) is a Crystal system where the Unit cell is in the shape of a Cube. The standard enthalpy of formation or "standard heat of formation" of a compound is the change of Enthalpy that accompanies the formation of 1 mole of a 98 kJ mol−1
Std enthalpy of combustion ΔcHo298	−250. The joule (written in lower case ˈdʒuːl or /ˈdʒaʊl/ (symbol J) is the SI unit of Energy measuring heat, Electricity The mole (symbol mol) is a unit of Amount of substance: it is an SI base unit, and almost the only unit to be used to measure this The standard enthalpy of combustion is the Enthalpy change when one mole of a substance completely reacts with oxygen under standard thermodynamic conditions (although 91 kJ mol−1
Standard molar entropy So298	14. In Chemistry, the standard molar entropy is the Entropy content of one mole of substance under standard conditions (not standard temperature and pressure 77 J mol−1 K−1
Hazards
R-phrases	R36, R37
S-phrases	S26, S36
Related compounds
Other anions	BP, BAs B4C, B2O3
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Boron nitride (BN) is a binary chemical compound, consisting of equal numbers of boron and nitrogen atoms. R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge Boron phosphide (BP is a chemical compound of Boron and Phosphorus. Boron arsenide is a chemical compound of Boron and Arsenic. It is a cubic ( Sphalerite) Semiconductor with a Lattice constant Boron carbide (chemical formula B4C is an extremely hard Ceramic material used in Tank Armor, Bulletproof vests and numerous Boron oxide is one of the oxides of Boron. It is white glassy and solid also known as diboron trioxide, formula B2O3 In Chemistry, the standard state of a material is its state at 1 bar (100 Kilopascals exactly A binary compound is a compound that contains two different elements such as NaCl (salt or Sodium chloride) Boron (ˈbɔərɒn is a Chemical element with Atomic number 5 and the chemical symbol B. Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Its empirical formula is therefore BN. Use in chemistry In Chemistry, the empirical formula of a Chemical compound is a simple expression of the relative number of each type of Atom Boron nitride is isoelectronic with carbon and, like carbon, boron nitrides exists as various polymorphic forms, one of which is analogous to diamond and one analogous to graphite. Two or more molecular entities ( Atoms Molecules Ions are described as being isoelectronic with each other if they have the same number of Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 Polymorphism in Materials science is the ability of a solid material to exist in more than one form or Crystal structure In Mineralogy, diamond is the allotrope of carbon where the carbon atoms are arranged in The Mineral graphite, as with Diamond and Fullerene, is one of the Allotropes of carbon. The diamond-like polymorph is one of the hardest materials known and the graphite-like polymorph is a useful lubricant.

Contents 1 Hexagonal BN 1.1 Preparation of hexagonal BN 2 Cubic boron nitride 2.1 Preparation of cubic BN 3 Other polymorphs of BN 3.1 w-BN 3.2 Rhombohedral boron nitride 3.3 Boron nitride fibers 4 Nanostructured BN 4.1 Boron nitride nanotubes 4.2 Boron nitride nanomesh 4.3 Amorphous boron nitride 4.4 BN-based fullerenes 5 Composites containing BN 6 See also 7 References 8 External links

Hexagonal BN

The graphite-like polymorph of boron nitride, known as hexagonal boron nitride, h-BN, α-BN, or g-BN (graphitic BN), and sometimes called "white graphite", is the most widely used polymorph. The Mineral graphite, as with Diamond and Fullerene, is one of the Allotropes of carbon. ^[1] The hexagonal polymorph is composed of layers of hexagonal sheets, analogous to graphite. The interlayer "registry" of these sheets differs, however, from the pattern seen for graphite, because the atoms are eclipsed, with boron atoms laying over and above nitrogen atoms. This registry reflects the polarity of the B-N bonds. The diminished covalency in BN results in diminished electrical conductivity relative to graphite, which is a semimetal that conducts electricity through a network of pi-bonds in the plane of its hexagonal sheets. A semimetal is a material with a small overlap in the energy of the conduction band and Valence bands However the bottom of the conduction band is The diminished electron-delocalizaton in hexagonal-BN is indicated by its absence of color, which signals a large band gap. In Solid state physics and related applied fields a band gap, also called an energy gap or bandgap, is an energy range in a solid where no electron states

Hexagonal BN is a lubricant at both low and high temperatures (up to 900 °C, even in oxidizing atmosphere). It is particularly useful lubricant in situations where the electrical conductivity or chemical reactivity of graphite would be problematic. Since the lubricity mechanism does not involve water molecules trapped between the layers, boron nitride lubricants can be used even in vacuum, e. g. for space applications.

Hexagonal boron nitride is stable in temperatures up to 1000 °C in air, 1400 °C in vacuum, and 2800 °C in an inert atmosphere. It has one of the best thermal conductivities of all electric insulators. It is fairly chemically inert and is not wetted by many melted materials (e. Wetting is the contact between a liquid and a solid surface resulting from intermolecular interactions when the two are brought together g. aluminium, copper, zinc, iron and steels, germanium, silicon, boron, cryolite, glass and halide salts).

Fine-grained h-BN is used in some cosmetics, paints, dental cements, and pencil leads. Paint is any Liquid, liquifiable or mastic composition which after application to a substrate in a thin layer is converted to an opaque Solid A pencil is a Writing or Drawing instrument consisting of a thin stick of Pigment (usually Graphite, but can also be coloured pigment or

Preparation of hexagonal BN

Hexagonal boron nitride is produced by the nitridation or ammonolysis of boron trioxide. Solvolysis is a special type of Nucleophilic substitution or elimination where the Nucleophile is a Solvent molecule Boron oxide is one of the oxides of Boron. It is white glassy and solid also known as diboron trioxide, formula B2O3 h-BN parts can be made by hot-pressing with subsequent machining; due to the mechanical hardness similar to graphite, the machining cost is low. The parts are made from boron nitride powders, using boron oxide as a sintering agent. Boron oxide is one of the oxides of Boron. It is white glassy and solid also known as diboron trioxide, formula B2O3 Sintering is a method for making objects from powder, by heating the material (below its Melting point - solid state sintering until its particles adhere Thin films of boron nitride can be obtained by chemical vapor deposition from boron trichloride and nitrogen precursors. Chemical vapor deposition (CVD is a Chemical process used to produce high-purity high-performance solid materials Boron trichloride is a Chemical compound with the formula BCl3 Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Industrial production is based on two reactions: melted boric acid with ammonia, and boric acid or alkaline borates with urea, guanidine, melamin, or other suitable organic nitrogen compounds in nitrogen atmosphere. Combustion of boron powder in nitrogen plasma at 5500 °C yields ultrafine boron nitride for lubricants and toners. In Physics and Chemistry, plasma is an Ionized Gas, in which a certain proportion of Electrons are free rather than being bound Ultrafine particles ( UFPs) are Nanoscale, less than 100 Nanometres Clusters of UFPs can be seen with the naked eye For the Irish surname see Toner (surname. Toner is a powder used in Laser printers and Photocopiers to form

α-BN, hexagonal

α-BN, hexagonal

β-BN, sphalerite structure

BN, wurtzite structure

Cubic boron nitride

Cubic boron nitride is extremely hard, although less so than diamond and some related materials. Sphalerite (( Zn, Fe) S) is a Mineral that is the chief Ore of Zinc. This article is about the mineral wurtzite For the wurtzite crystal structure see Wurtzite (crystal structure. In Mineralogy, diamond is the allotrope of carbon where the carbon atoms are arranged in Also like diamond, cubic boron nitride is an electrical insulator but an excellent conductor of heat. An insulator, also called a Dielectric, is a material that resists the flow of Electric current. This diamond-like polymorph, known as cubic boron nitride, c-BN, β-BN, or z-BN (after zinc blende crystalline structure), is widely used as an abrasive for industrial tools. In Mineralogy, diamond is the allotrope of carbon where the carbon atoms are arranged in Sphalerite (( Zn, Fe) S) is a Mineral that is the chief Ore of Zinc. An abrasive is a material often a Mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away Its usefulness arises from its insolubility in iron, nickel, and related alloys at high temperatures, whereas diamond is soluble in these metals to give carbides. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Nickel (ˈnɪkəl is a metallic Chemical element with the symbol Ni and Atomic number 28 An alloy is a Solid solution or Homogeneous mixture of two or more elements, at least one of which is a Metal, which itself has Polycrystalline c-BN abrasives are therefore used for machining steel, whereas diamond abrasives are preferred for aluminium alloys, ceramics, and stone. Like diamond, cubic BN has good thermal conductivity, caused by phonons. In Physics, a phonon is a quantized mode of vibration occurring in a rigid crystal lattice, such as the Atomic lattice of a Solid In contact with oxygen at high temperatures, BN forms a passivation layer of boron oxide. Boron nitride binds well with metals, due to formation of interlayers of metal borides or nitrides. Materials with cubic boron nitride crystals are often used in the tool bits of cutting tools. The term tool bit generally refers to a non-rotary cutting tool used in metal lathes, Shapers and planers. In the context of Metalworking, a cutting tool, is any tool that is used to remove metal from the workpiece by means of shear deformation For grinding applications, softer binders, e. g. resin, porous ceramics, and soft metals, are used. Ceramic binders can be used as well. Commercial products are known under names "Borazon" (by Diamond Innovations), and "Elbor" or "Cubonite" (by Russian vendors).

Sintered cubic boron nitride is an electrically insulating heatsink material of potential value in microelectronics. A heat sink (or heatsink) is an environment or object that absorbs and dissipates heat from another object using Thermal contact (either direct or radiant Microelectronics is a subfield of Electronics. Microelectronics as the name suggestsis related to the study and manufacture or Microfabrication, of electronic

Preparation of cubic BN

Cubic boron nitride is produced by treating hexagonal boron nitride at high pressure and temperature, much as synthetic diamond is produced from graphite. Synthetic diamond (also known variously as lab-created, manufactured, lab-grown or cultured diamond) is a term used to describe Diamond Direct conversion of hexagonal boron nitride to the cubic form occurs at pressures up to 18 GPa and temperatures between 1730-3230 °C; addition of small amount of boron oxide can lower the required pressure to 4-7 GPa and temperature to 1500 °C. Industrially, BN conversion using catalysts is used instead; the catalyst materials differ for different production methods, eg. lithium, potassium, or magnesium, their nitrides, their fluoronitrides, water with ammonium compounds, or hydrazine. Other industrial synthesis methods use crystal growth in temperature gradient, or explosive shock wave. For the music album by Converter see Shock Front For the 1977 horror film see Shock Waves A shock wave (also called The shock wave method is used to produce material called heterodiamond, a superhard compound of boron, carbon, and nitrogen. Heterodiamond is a Superhard material containing Boron, Carbon, and Nitrogen ( BCN)

Low-pressure deposition of thin films of cubic boron nitride is possible. For selective etching of the deposited hexagonal phase during chemical vapor deposition, boron trifluoride is used (cf. Chemical vapor deposition (CVD is a Chemical process used to produce high-purity high-performance solid materials Boron trifluoride is the Chemical compound with the formula BF3 use of atomic hydrogen for selective etching of graphite during deposition of diamond films). Ion beam deposition, Plasma Enhanced CVD, pulsed laser deposition, reactive sputtering, and other physical vapor deposition methods are used as well. Ion Beam Deposition (IBD is a process of applying materials to a target through the application of an Ion beam. Plasma Enhanced Chemical Vapor Deposition (PECVD is a process used to deposit thin films from a Gas state ( Vapor) to a Solid state on some substrate Pulsed laser deposition (PLD is a Thin film deposition (specifically a Physical vapor deposition, PVD technique where a high power pulsed Laser beam is Physical vapor deposition (PVD is a variety of vacuum deposition and is a general term used to describe any of a variety of methods to deposit Thin films by the condensation

Other polymorphs of BN

w-BN

Known as w-BN, hexagonal boron nitride is a superhard phase that occurs at high pressures. This hexagonal phase differs from the layered graphitic material: it adopts the wurtzite structure. This article is about the mineral wurtzite For the wurtzite crystal structure see Wurtzite (crystal structure.

Rhombohedral boron nitride

Rhombohedral boron nitride is similar to hexagonal boron nitride. It is formed transitionally during conversion of cubic BN to hexagonal form.

Boron nitride fibers

Hexagonal BN can be prepared in the form of fibers, structurally similar to carbon fibers, sometimes called "white carbon fiber. " They can be prepared by thermal decomposition of extruded borazine fibers with addition of boron oxide in nitrogen at 1800 °C. Borazine is an Inorganic compound composed of the elements Boron, Nitrogen and Hydrogen. Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 The material also arises by the thermal decomposition of cellulose fibers impregnated with boric acid or ammonium tetraborate in an atmosphere of ammonia and nitrogen above 1000 °C. Cellulose is an Organic compound with the formula, a Polysaccharide consisting of a linear chain of several hundred to over ten thousand β(1→4 Boric acid, also called boracic acid or orthoboric acid or Acidum Boricum, is a mild Acid often used as an Antiseptic, Insecticide Boron nitride fibers are used as reinforcement in composite materials, with the matrix materials ranging from organic resins to ceramics to metals (see Metal matrix composites). Composite materials (or composites for short are engineered Materials made from two or more constituent materials with significantly different physical or chemical A metal matrix composite (MMC is Composite material with at least two constituent parts one being a Metal.

Nanostructured BN

Boron nitride nanotubes

Like BN fibers, boron nitride nanotubes(BNNTs) show promise for aerospace applications where integration of boron and in particular the light isotope of boron (¹⁰B) into structural materials improves their radiation-shielding properties, due to ¹⁰B's neutron absorption properties. Such ¹⁰BN materials are of particular theoretical value as composite structural material in future manned interplanetary spacecraft, where absorption-shielding from cosmic ray spallation neutrons is expected to be a particular asset in light construction materials. [1]

Boron nitride nanomesh

Boron nitride nanomesh is a new inorganic nanostructured two-dimensional material. The nanomesh is a new Inorganic nanostructured two-dimensional material similar to Graphene. Traditionally inorganic compounds are considered to be of mineral not biological origin It consists of a single layer of hexagonal boron nitride on rhodium or ruthenium, forming a highly regular mesh. Rh redirects here For other uses see Rh (disambiguation Rhodium (ˈroʊdiəm is a Chemical element with the symbol Ruthenium (ruːˈθiːniəm is a Chemical element that has the symbol Ru and Atomic number 44 The distance between two pore centers is 3. 2 nanometers and the pores are 0. A nanometre ( American spelling: nanometer, symbol nm) ( Greek: νάνος nanos dwarf; μετρώ metrό count) is a 05 nanometer deep. A nanometre ( American spelling: nanometer, symbol nm) ( Greek: νάνος nanos dwarf; μετρώ metrό count) is a The boron nitride nanomesh is stable under vacuum, air and some liquids, but also up to temperatures of 796 ^oC. In addition, it shows the extraordinary ability to trap molecules and metallic clusters. In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by In physics the term clusters denotes small multiatom particles These characteristics promise interesting applications of the nanomesh in nanotechnology. The nanomesh is a new Inorganic nanostructured two-dimensional material similar to Graphene. Nanotechnology, sometimes shortened to nanotech, refers to a field of Applied science whose theme is the control of matter on an Atomic and Molecular

Amorphous boron nitride

Layers of amorphous boron nitride (a-BN) are used in some semiconductor devices, eg. Semiconductor devices are Electronic components that exploit the electronic properties of Semiconductor materials principally Silicon, Germanium MISFETs. A MISFET is a Metal – insulator – Semiconductor Field-effect transistor. They can be prepared by chemical decomposition of trichloroborazine with caesium, or by thermal chemical vapor deposition methods. Caesium or cesium (ˈsiːziəm is the Chemical element with the symbol Cs and Atomic number 55 Chemical vapor deposition (CVD is a Chemical process used to produce high-purity high-performance solid materials Thermal CVD can be also used for deposition of h-BN layers, or at high temperatures, c-BN.

BN-based fullerenes

The fullerene-like forms of boron nitride can be synthesized and structurally resemble carbon carbon nanotubes. "C60" and "C-60" redirect here For other uses see C60 (disambiguation. See also Graphene, Buckypaper Carbon nanotubes (CNTs are Allotropes of carbon with a nanostructure that can have a length-to-diameter The recently discovered boron nitride nanotubes are an important development due to their homogeneous electronic behavior. That is, tubes of different chiralities are all semiconductor materials with the same (approximate) band gap. The term chiral (pronounced /ˈkaɪɹ(əl̩/ is used to describe an object that is non- superimposable on its mirror image A semiconductor' is a Solid material that has Electrical conductivity in between a conductor and an insulator; it can vary over that

Composites containing BN

Addition of boron nitride to silicon nitride ceramics improves the thermal shock resistance of the resulting material. Silicon nitride (Si3N4 is a hard solid substance It is the main component in silicon nitride Ceramics which have relatively good shock resistance Thermal shock is the name given to cracking as a result of rapid temperature change For the same purpose, BN is added also to silicon nitride-alumina and titanium nitride-alumina ceramics. Titanium nitride ( (sometimes known as Tinite or TiNite is an extremely hard Ceramic material often used as a coating on Titanium alloy, Steel, Other materials being reinforced with BN are e. g. alumina and zirconia, borosilicate glasses, glass ceramics, enamels, and composite ceramics with titanium boride-boron nitride and titanium boride-aluminium nitride-boron nitride and silicon carbide-boron nitride composition. Zirconia redirects here For the Sailor Moon character see Dead Moon Circus. Borosilicate glass is a type of Glass with the main glass-forming constituents Silica and Boron oxide. Glass-ceramic materials share many properties with both Glass and more traditional crystalline Ceramics It is formed as a glass and then made to Crystallize In a discussion of Material science, enamel (or vitreous enamel or porcelain enamel in U Titanium Diboride (chemical formula TiB2 is an extremely hard Ceramic compound (33 GPa composed of Titanium and Boron that has very good Aluminium nitride ( Al[[Nitrogen N]] is a Nitride of Aluminium. Silicon carbide ( is a compound of Silicon and Carbon bonded together to form Ceramics but it also occurs in nature as the extremely rare mineral

Due to its excellent dielectric and thermal properties, BN is used in electronics e. g. as a substrate for semiconductors, microwave-transparent windows, structural material for seals, electrodes and catalyst carriers in fuel cells and batteries. A fuel cell is an electrochemical conversion device It produces electricity from Fuel (on the Anode side and an oxidant (on the

h-BN can be included in ceramics, alloys, resins, plastics, rubbers and other materials, giving them self-lubricating properties. Such materials are suitable for construction of e. g. bearings. Plastics filled with BN have decreased thermal expansion, increased thermal conductivity, increased electrical insulation properties, and cause reduced wear to adjacent parts.

See also

• Beta carbon nitride
• Borazon
• Boron phosphide
• Boron suboxide
• Aluminium nitride
• Wide bandgap semiconductors

References

External links

• National Pollutant Inventory: Boron and Compounds
• Fiz Chemie Berlin thermophysical database
• Materials Safety Data Sheet at University of Oxford

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