In chemistry, a nitride is a compound of nitrogen where nitrogen has a formal oxidation state of −3. Nitrides are a large class of compounds with a wide range of applications; the nitride ion, N3−, is never encountered in protic solution because it is so basic that it would be protonated immediately. Its ionic radius is estimated to be 140 pm. Like carbides, nitrides are refractory materials owing to their high lattice energy which reflects the strong attraction of "N3−" for the metal cation. Thus, titanium nitride and silicon nitride are used as cutting hard coatings. Hexagonal boron nitride, which adopts a layered structure, is a useful high-temperature lubricant akin to molybdenum disulfide. Nitride compounds have large band gaps, thus nitrides are insulators or wide bandgap semiconductors; the wide band gap material gallium nitride is prized for emitting blue light in LEDs. Like some oxides, nitrides can absorb hydrogen and have been discussed in the context of hydrogen storage, e.g. lithium nitride.
Classification of such a varied group of compounds is somewhat arbitrary. Compounds where nitrogen is not assigned −3 oxidation state are not included, such as nitrogen trichloride where the oxidation state is +3. Only one alkali metal nitride is stable, the purple-reddish lithium nitride, which forms when lithium burns in an atmosphere of N2. Sodium nitride remains a laboratory curiosity; the nitrides of the alkaline earth metals have the formula. Examples include Be3N2, Mg3N2, Ca3N2, Sr3N2; the nitrides of electropositive metals hydrolyze upon contact with water, including the moisture in the air: Mg3N2 + 6 H2O → 3 Mg2 + 2 NH3 Boron nitride exists as several forms. Nitrides of silicon and phosphorus are known, but only the former is commercially important; the nitrides of aluminium and indium adopt diamond-like wurtzite structure in which each atom occupies tetrahedral sites. For example, in aluminium nitride, each aluminium atom has four neighboring nitrogen atoms at the corners of a tetrahedron and each nitrogen atom has four neighboring aluminium atoms at the corners of a tetrahedron.
This structure is like hexagonal diamond. Thallium nitride, Tl3N is known, but thallium nitride, TlN, is not. For the group 3 metals, ScN and YN are both known. Group 4, 5, 6 transition metals, the titanium and chromium groups all form nitrides, they are chemically stable. Representative is titanium nitride. Sometimes these materials are called "interstitial nitrides." Nitrides of the Group 7 and 8 transition metals decompose readily. For example, iron nitride, Fe2N decomposes at 200 °C. Platinum nitride and osmium nitride may contain N2 units, as such should not be called nitrides. Nitrides of heavier members from group 11 and 12 are less stable than copper nitride, Cu3N and Zn3N2: dry silver nitride is a contact explosive which may detonate from the slightest touch a falling water droplet. Many metals form molecular nitrido complexes; the main group elements form some molecular nitrides. Cyanogen and tetrasulfur tetranitride are rare examples of a molecular binary nitrides, they dissolve in nonpolar solvents.
Both undergo polymerization. S4N4 is unstable with respect to the elements, but less so that the isostructural Se4N4. Heating S4N4 gives a polymer, a variety of molecular sulfur nitride anions and cations are known. Related to but distinct from nitride is pernitride, N2−2
Copper phosphide, Cu3P copper phosphide, cuprous phosphide and phosphor copper, is a compound of copper and phosphorus, a phosphide of copper. It has the appearance of yellowish-grey brittle mass of crystalline structure, it does not react with water. Copper phosphide has a role in copper alloys, namely in phosphor bronze, it is a good deoxidizer of copper. Copper phosphide can be produced in a reverberatory furnace or in a crucible, e.g. by a reaction of red phosphorus with a copper-rich material. It can be prepared photochemically, by irradiating cupric hypophosphite with ultraviolet radiation; when subjected to ultraviolet light, copper phosphide shows fluorescence. A blue-black film of copper phosphide forms on white phosphorus when subjected to a solution of copper salt; the particles can be removed, helped by their fluorescence. Formation of protective layer of copper phosphide is used in cases of phosphorus ingestion, when gastric lavage with copper sulfate is employed as part of the cure
Indium phosphide is a binary semiconductor composed of indium and phosphorus. It has a face-centered cubic crystal structure, identical to that of GaAs and most of the III-V semiconductors. Indium phosphide can be prepared from the reaction of white phosphorus and indium iodide at 400 °C. by direct combination of the purified elements at high temperature and pressure, or by thermal decomposition of a mixture of a trialkyl indium compound and phosphine. InP is used in high-power and high-frequency electronics because of its superior electron velocity with respect to the more common semiconductors silicon and gallium arsenide, it was used with indium gallium arsenide to make a record breaking pseudomorphic heterojunction bipolar transistor that could operate at 604 GHz. It has a direct bandgap, making it useful for optoelectronics devices like laser diodes; the company Infinera uses indium phosphide as its major technological material for manufacturing photonic integrated circuits for the optical telecommunications industry, to enable wavelength-division multiplexing applications.
InP is used as a substrate for epitaxial indium gallium arsenide based opto-electronic devices. The application fields of InP splits up into three main areas, it is used as the basis - for optoelectronic components - for high-speed electronics. - for photovoltaics There is still a vastly under-utilized, yet technically exciting zone in the electromagnetic spectrum between microwaves and infrared referred to as “Terahertz”. Electromagnetic waves in this range possess hybrid properties they show high-frequency- and optical characteristics simultaneously. InP based. InP based lasers and LEDs can emit light in the broad range of 1200 nm up to 12 µm; this light is used for fibre based Telecom and Datacom applications in all areas of the digitalised world. Light is used for sensing applications. On one hand there are spectroscopic applications, where a certain wavelength is needed to interact with matter to detect diluted gases for example. Optoelectronic terahertz is used in ultra-sensitive spectroscopic analysers, thickness measurements of polymers and for the detection of multilayer coatings in the automotive industry.
On the other hand there is a huge benefit of specific InP lasers. The radiation can not harm the retina. InP lasers in LiDAR will be a key component for the mobility of the future and the automation industry. Indium Phosphide is used to produce efficient lasers, sensitive photodetectors and modulators in the wavelength window used for telecommunications, i.e. 1550 nm wavelengths, as it is a direct bandgap III-V compound semiconductor material. The wavelength between about 1510 nm and 1600 nm has the lowest attenuation available on optical fibre. InP is a used material for the generation of laser signals and the detection and conversion of those signals back to electronic form. Wafer diameters range from 2-4 inches. Applications are: • Long-haul optical fibre connections over great distance up to 5000 km >10 Tbit/s • Metro ring access networks • Company networks and data center • Fibre to the home • Connections to wireless 3G, LTE and 5G base stations • Free space satellite communication Spectroscopic Sensing aiming environmental protection and identification of dangerous substances • A growing field is sensing based on the wavelength regime of InP.
One example for Gas Spectroscopy is drive test equipment with real-time measurement of. • Another example is FT-IR-Spectrometer VERTEX with a terahertz source. The terahertz radiation is generated from the beating signal of 2 InP lasers and an InP antenna that transforms the optical signal to the terahertz regime. • Stand-Off detection of traces of explosive substances on surfaces, e.g. for safety applications on airports or crime scene investigation after assassination attempts. • Quick verification of traces of toxic substances in gases and liquids or surface contaminations down to the ppb level. • Spectroscopy for non-destructive product control of e.g. food • Spectroscopy for many novel applications in air pollution control are being discussed today and implementations are on the way. Discussed in the LiDAR arena is the wavelength of the signal. While some players have opted for 830-to-940-nm wavelengths to take advantage of available optical components, companies are turning to longer wavelengths in the also-well-served 1550-nm wavelength band, as those wavelengths allow laser powers 100 times higher to be employed without compromising public safety.
Lasers with emission wavelengths longer than ≈ 1.4 μm are called “eye-safe” because light in that wavelength range is absorbed in the eye's cornea and vitreous body and therefore cannot damage the sensitive retina). • LiDAR-based sensor technology can provide a high level of object identification and classification with three-dimensional imaging techniques. • The automotive industry will adopt a chip-based, low cost solid state LiDAR sensor technology instead of large, mechanical LiDAR systems in the future. • For the most advanced chip-based LiDAR systems, InP will play an important role and will enable autonomous driving.. The longer eye safe wavelength is more appropriate dealing with real world conditions like dust and rain. Today´s semiconduc
Nitrogen is a chemical element with symbol N and atomic number 7. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772. Although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time, Rutherford is accorded the credit because his work was published first; the name nitrogène was suggested by French chemist Jean-Antoine-Claude Chaptal in 1790, when it was found that nitrogen was present in nitric acid and nitrates. Antoine Lavoisier suggested instead the name azote, from the Greek ἀζωτικός "no life", as it is an asphyxiant gas. Nitrogen is the lightest member of group 15 of the periodic table called the pnictogens; the name comes from the Greek πνίγειν "to choke", directly referencing nitrogen's asphyxiating properties. It is a common element in the universe, estimated at about seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bind to form dinitrogen, a colourless and odorless diatomic gas with the formula N2.
Dinitrogen forms about 78 % of Earth's atmosphere. Nitrogen occurs in all organisms in amino acids, in the nucleic acids and in the energy transfer molecule adenosine triphosphate; the human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen and hydrogen. The nitrogen cycle describes movement of the element from the air, into the biosphere and organic compounds back into the atmosphere. Many industrially important compounds, such as ammonia, nitric acid, organic nitrates, cyanides, contain nitrogen; the strong triple bond in elemental nitrogen, the second strongest bond in any diatomic molecule after carbon monoxide, dominates nitrogen chemistry. This causes difficulty for both organisms and industry in converting N2 into useful compounds, but at the same time means that burning, exploding, or decomposing nitrogen compounds to form nitrogen gas releases large amounts of useful energy. Synthetically produced ammonia and nitrates are key industrial fertilisers, fertiliser nitrates are key pollutants in the eutrophication of water systems.
Apart from its use in fertilisers and energy-stores, nitrogen is a constituent of organic compounds as diverse as Kevlar used in high-strength fabric and cyanoacrylate used in superglue. Nitrogen is a constituent including antibiotics. Many drugs are mimics or prodrugs of natural nitrogen-containing signal molecules: for example, the organic nitrates nitroglycerin and nitroprusside control blood pressure by metabolizing into nitric oxide. Many notable nitrogen-containing drugs, such as the natural caffeine and morphine or the synthetic amphetamines, act on receptors of animal neurotransmitters. Nitrogen compounds have a long history, ammonium chloride having been known to Herodotus, they were well known by the Middle Ages. Alchemists knew nitric acid as aqua fortis, as well as other nitrogen compounds such as ammonium salts and nitrate salts; the mixture of nitric and hydrochloric acids was known as aqua regia, celebrated for its ability to dissolve gold, the king of metals. The discovery of nitrogen is attributed to the Scottish physician Daniel Rutherford in 1772, who called it noxious air.
Though he did not recognise it as an different chemical substance, he distinguished it from Joseph Black's "fixed air", or carbon dioxide. The fact that there was a component of air that does not support combustion was clear to Rutherford, although he was not aware that it was an element. Nitrogen was studied at about the same time by Carl Wilhelm Scheele, Henry Cavendish, Joseph Priestley, who referred to it as burnt air or phlogisticated air. Nitrogen gas was inert enough that Antoine Lavoisier referred to it as "mephitic air" or azote, from the Greek word άζωτικός, "no life". In an atmosphere of pure nitrogen, animals died and flames were extinguished. Though Lavoisier's name was not accepted in English, since it was pointed out that all gases are mephitic, it is used in many languages and still remains in English in the common names of many nitrogen compounds, such as hydrazine and compounds of the azide ion, it led to the name "pnictogens" for the group headed by nitrogen, from the Greek πνίγειν "to choke".
The English word nitrogen entered the language from the French nitrogène, coined in 1790 by French chemist Jean-Antoine Chaptal, from the French nitre and the French suffix -gène, "producing", from the Greek -γενής. Chaptal's meaning was that nitrogen is the essential part of nitric acid, which in turn was produced from nitre. In earlier times, niter had been confused with Egyptian "natron" – called νίτρον in Greek – which, despite the name, contained no nitrate; the earliest military and agricultural applications of nitrogen compounds used saltpeter, most notably in gunpowder, as fertiliser. In 1910, Lord Rayleigh discovered that an electrical discharge in nitrogen gas produced "active nitrogen", a monatomic allotrope of nitrogen; the "whirling cloud of brilliant yellow light
Phosphorus pentachloride is the chemical compound with the formula PCl5. It is one of the most important phosphorus chlorides, others being PCl3 and POCl3. PCl5 finds use as a chlorinating reagent, it is a colourless, water-sensitive and moisture-sensitive solid, although commercial samples can be yellowish and contaminated with hydrogen chloride. The structures for the phosphorus chlorides are invariably consistent with VSEPR theory; the structure of PCl5 depends on its environment. Gaseous and molten PCl5 is a neutral molecule with trigonal bipyramidal symmetry; the hypervalent nature of this species can be explained with the inclusion of non-bonding molecular orbitals or resonance. This trigonal bipyramidal structure persists in nonpolar solvents, such as CS2 and CCl4. In the solid state PCl5 is an ionic compound, formulated PCl+4PCl−6. In solutions of polar solvents, PCl5 undergoes self-ionization. Dilute solutions dissociate according to the following equilibrium: PCl5 ⇌ PCl+4 + Cl−At higher concentrations, a second equilibrium becomes more prevalent: 2 PCl5 ⇌ PCl+4 + PCl−6The cation PCl+4 and the anion PCl−6 are tetrahedral and octahedral, respectively.
At one time, PCl5 in solution was thought to form a dimeric structure, P2Cl10, but this suggestion is not supported by Raman spectroscopic measurements. AsCl5 and SbCl5 adopt trigonal bipyramidal structures; the relevant bond distances are 211 pm, 221 pm, 227 pm, 233.3 pm. At low temperatures, SbCl5 converts to the dimer, dioctahedral Sb2Cl10, structurally related to niobium pentachloride. PCl5 is prepared by the chlorination of PCl3; this reaction is used to produce around 10,000 tonnes of PCl5 per year. PCl3 + Cl2 ⇌ PCl5 PCl5 exists in equilibrium with PCl3 and chlorine, at 180 °C the degree of dissociation is about 40%; because of this equilibrium, samples of PCl5 contain chlorine, which imparts a greenish coloration. In its most characteristic reaction, PCl5 reacts upon contact with water to release hydrogen chloride and give phosphorus oxides; the first hydrolysis product is phosphorus oxychloride: PCl5 + H2O → POCl3 + 2 HClIn hot water, hydrolysis proceeds to orthophosphoric acid: PCl5 + 4 H2O → H3PO4 + 5 HCl In synthetic chemistry, two classes of chlorination are of interest: oxidative chlorinations and substitutive chlorinations.
Oxidative chlorinations entail the transfer of Cl2 from the reagent to the substrate. Substitutive chlorinations entail replacement of OH groups with chloride. PCl5 can be used for both processes. Upon treatment with PCl5, carboxylic acids convert to the corresponding acyl chloride; the following mechanism has been proposed: It converts alcohols to alkyl chlorides. Thionyl chloride is more used in the laboratory because the resultant sulfur dioxide is more separated from the organic products than is POCl3. PCl5 reacts with a tertiary amides, such as dimethylformamide, to give dimethylchloromethyleneammonium chloride, called the Vilsmeier reagent, Cl. More a related salt is generated from the reaction of DMF and POCl3; such reagents are useful in the preparation of derivatives of benzaldehyde by formylation and for the conversion of C−OH groups into C−Cl groups. It is renowned for the conversion of C=O groups to CCl2 groups. For example and phosphorus pentachloride react to give the diphenyldichloromethane: 2CO + PCl5 → 2CCl2 + POCl3The electrophilic character of PCl5 is highlighted by its reaction with styrene to give, after hydrolysis, phosphonic acid derivatives.
Both PCl3 and PCl5 convert R3COH groups to the chloride R3CCl. The pentachloride is however a source of chlorine in many reactions, it chlorinates benzylic CH bonds. PCl5 bears a greater resemblance to SO2Cl2 a source of Cl2. For oxidative chlorinations on the laboratory scale, sulfuryl chloride is preferred over PCl5 since the gaseous SO2 by-product is separated; as for the reactions with organic compounds, the use of PCl5 has been superseded by SO2Cl2. The reaction of phosphorus pentoxide and PCl5 produces POCl3: 6 PCl5 + P4O10 → 10 POCl3PCl5 chlorinates nitrogen dioxide to form unstable nitryl chloride: PCl5 + 2 NO2 → PCl3 + 2 NO2Cl 2 NO2Cl → 2 NO2 + Cl2PCl5 is a precursor for lithium hexafluorophosphate, LiPF6, an electrolyte in lithium ion batteries. LiPF6 is produced by the reaction of PCl5 with lithium fluoride, with lithium chloride as a side product: PCl5 + 6 LiF → LiPF6 + 5 LiCl PCl5 is a dangerous substance as it reacts violently with water, it is corrosive when in contact with skin and can be fatal when inhaled.
Phosphorus pentachloride was first prepared in 1808 by the English chemist Humphry Davy. Davy's analysis of phosphorus pentachloride was inaccurate. Phosphorus halides Phosphorus trichloride Phosphoryl chloride Phosphorus trifluorodichloride The period 3 chlorides International Chemical Safety Card 0544 CDC - NIOSH Pocket Guide to Chemical Hazards
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table, a reactive nonmetal, an oxidizing agent that forms oxides with most elements as well as with other compounds. By mass, oxygen is the third-most abundant element in the universe, after helium. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2. Diatomic oxygen gas constitutes 20.8% of the Earth's atmosphere. As compounds including oxides, the element makes up half of the Earth's crust. Dioxygen is used in cellular respiration and many major classes of organic molecules in living organisms contain oxygen, such as proteins, nucleic acids and fats, as do the major constituent inorganic compounds of animal shells and bone. Most of the mass of living organisms is oxygen as a component of water, the major constituent of lifeforms. Oxygen is continuously replenished in Earth's atmosphere by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide.
Oxygen is too chemically reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. Another form of oxygen, ozone absorbs ultraviolet UVB radiation and the high-altitude ozone layer helps protect the biosphere from ultraviolet radiation. However, ozone present at the surface is a byproduct of thus a pollutant. Oxygen was isolated by Michael Sendivogius before 1604, but it is believed that the element was discovered independently by Carl Wilhelm Scheele, in Uppsala, in 1773 or earlier, Joseph Priestley in Wiltshire, in 1774. Priority is given for Priestley because his work was published first. Priestley, called oxygen "dephlogisticated air", did not recognize it as a chemical element; the name oxygen was coined in 1777 by Antoine Lavoisier, who first recognized oxygen as a chemical element and characterized the role it plays in combustion. Common uses of oxygen include production of steel and textiles, brazing and cutting of steels and other metals, rocket propellant, oxygen therapy, life support systems in aircraft, submarines and diving.
One of the first known experiments on the relationship between combustion and air was conducted by the 2nd century BCE Greek writer on mechanics, Philo of Byzantium. In his work Pneumatica, Philo observed that inverting a vessel over a burning candle and surrounding the vessel's neck with water resulted in some water rising into the neck. Philo incorrectly surmised that parts of the air in the vessel were converted into the classical element fire and thus were able to escape through pores in the glass. Many centuries Leonardo da Vinci built on Philo's work by observing that a portion of air is consumed during combustion and respiration. In the late 17th century, Robert Boyle proved. English chemist John Mayow refined this work by showing that fire requires only a part of air that he called spiritus nitroaereus. In one experiment, he found that placing either a mouse or a lit candle in a closed container over water caused the water to rise and replace one-fourteenth of the air's volume before extinguishing the subjects.
From this he surmised that nitroaereus is consumed in both combustion. Mayow observed that antimony increased in weight when heated, inferred that the nitroaereus must have combined with it, he thought that the lungs separate nitroaereus from air and pass it into the blood and that animal heat and muscle movement result from the reaction of nitroaereus with certain substances in the body. Accounts of these and other experiments and ideas were published in 1668 in his work Tractatus duo in the tract "De respiratione". Robert Hooke, Ole Borch, Mikhail Lomonosov, Pierre Bayen all produced oxygen in experiments in the 17th and the 18th century but none of them recognized it as a chemical element; this may have been in part due to the prevalence of the philosophy of combustion and corrosion called the phlogiston theory, the favored explanation of those processes. Established in 1667 by the German alchemist J. J. Becher, modified by the chemist Georg Ernst Stahl by 1731, phlogiston theory stated that all combustible materials were made of two parts.
One part, called phlogiston, was given off when the substance containing it was burned, while the dephlogisticated part was thought to be its true form, or calx. Combustible materials that leave little residue, such as wood or coal, were thought to be made of phlogiston. Air did not play a role in phlogiston theory, nor were any initial quantitative experiments conducted to test the idea. Polish alchemist and physician Michael Sendivogius in his work De Lapide Philosophorum Tractatus duodecim e naturae fonte et manuali experientia depromti described a substance contained in air, referring to it as'cibus vitae', this substance is identical with oxygen. Sendivogius, during his experiments performed between 1598 and 1604, properly recognized that the substance is equivalent to the gaseous byproduct released by the thermal decomposition of potassium nitrate. In Bugaj’s view, the isolation of oxygen and the proper association of the substance to that part of air, required for life, lends sufficient weight to the discovery of oxygen by Sendivogius.
Methylidyne called carbyne, is an organic compound with the chemical formula CH•. Methylidyne is the simplest carbyne, it is a reactive gas, destroyed in ordinary conditions but is abundant in the interstellar medium. In October 2016, astronomers reported that the basic chemical ingredients of life – the carbon-hydrogen molecule, the carbon-hydrogen positive ion, the carbon ion – are the result of ultraviolet light from stars, rather than in other ways, such as the result of turbulent events related to supernovae and young stars, as thought earlier; these results have given new light to the formation of organic compounds in the early development of life on earth. The trivial name carbyne is the preferred IUPAC name; the systematic names methylidyne, hydridocarbon, valid IUPAC names, are constructed according to the substitutive and additive nomenclatures, respectively. Methylidyne is viewed as methane with three hydrogen atoms removed. By default, this name pays no regard to the radicality of methylidyne.
When the radicality is considered, the radical states with one unpaired electron are named methylylidene, whereas the radical excited states with three unpaired electrons are named methanetriyl. As an odd-electron species, CH is a radical; the ground state is a doublet. The first two excited states are a doublet; the quartet lies at 71 kJ above the ground state. Reactions of the doublet radical with non-radical species involves insertion or addition, whereas reactions of the quartet radical involves only abstraction. • + H2O → • + H2 or • 3• + H2O → + • Methylidyne-like species are implied intermediates in the Fischer–Tropsch process, the hydrogenation of CO into hydrocarbons. Methylidyne entities are assumed to bond to the catalyst's surface. A hypothetical sequence is: MnCO + 1/2 H2 → MnCOH MnCOH + H2 → MnCH + H2OA molecular example of an MnCH is HCCo39. MnCH + 1/2 H2 → MnCH2The methylene ligand is poised couple to CO or to another methylene, thereby growing the C–C chain; the methylylidyne group can exhibit both Lewis basic character.
Such behavior is only of theoretical interest. Methylidine can be prepared from bromoform. Methylene group Methylene bridge