Phosphine
IUPAC name	Phosphane
Other names	Phosphine Phosphamine Phosphorus hydride Phosphorated hydrogen
Identifiers
CAS number	[7803-51-2]
Properties
Molecular formula	PH3
Molar mass	34. IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to 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) 00 g/mol
Appearance	colorless gas
Density	1. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 379 g/l, gas (25 °C)
Melting point	−134 °C
Boiling point	−87. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid 8 °C
Solubility in water	31. 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. 2 mg/100 ml (17 °C)
Structure
Molecular shape	Trigonal pyramidal
Dipole moment	0. Molecular geometry or molecular structure is the three- Dimensional arrangement of the Atoms that constitute a Molecule. In physics there are two kinds of dipoles ( Hellènic: di(s- = two- and pòla = pivot hinge An electric dipole is a 58 D
Hazards
EU classification	Highly flammable (F+) Very toxic (T+) Dangerous for the environment (N)
NFPA 704	4 3 2
R-phrases	R12, R17, R26, R34, R50
S-phrases	(S1/2), S28, S36/37, S45, S61, S63
Flash point	flammable gas
Autoignition temperature	38 °C (see text)
Related compounds
Other cations	Ammonia Arsine Stibine Bismuthine
Related compounds	Trimethylphosphine Triphenylphosphine
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Phosphine is the common name for phosphorus hydride (PH₃), also known by the IUPAC name phosphane and, occasionally, phosphamine. The debye (symbol D) is a non- SI, CGS unit of electrical dipole moment. Council Directive 67/548/EEC of 27 June 1967 on the approximation of laws regulations and administrative provisions relating to the classification packaging and labelling Symbolism The four divisions are typically color-coded with blue indicating level of Health Hazard, red indicating 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 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. 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. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. The flash point of a flammable liquid is the lowest Temperature at which it can form an ignitable mixture in air The autoignition temperature or kindling point of a substance is the lowest temperature at which it will spontaneously ignite in a normal atmosphere without an external 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 Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Arsine is the chemical compound with the formula As[[hydrogen H]]3 Stibine is the Chemical compound with the formula SbH3 This colourless gas is the principal Covalent hydride of Antimony and a heavy analogue Bismuthine is the Chemical compound with the formula BiH3 As the heaviest analogue of Ammonia, BiH3 is unstable decomposing to Bismuth Trimethylphosphine is the Chemical compound with the formula P(CH33 commonly abbreviated PMe3 Triphenylphosphine (in Europe triphenylphosphane is a common Organophosphorus compound with the formula P(C6H53 - often abbreviated to In Chemistry, the standard state of a material is its state at 1 bar (100 Kilopascals exactly The International Union of Pure and Applied Chemistry ( IUPAC) (aɪjuːpæk or ay-yoo-pec) is an international Non-governmental organization It is a colorless, flammable gas with a boiling point of −88 °C at standard pressure. In Physical sciences standard conditions for temperature and pressure are Standard sets of conditions for experimental measurements to allow comparisons to be made Pure phosphine is odourless, but technical grade phosphine has a highly unpleasant odor like garlic or rotting fish, due to the presence of substituted phosphine and diphosphine (P₂H₄). Allium sativum L, commonly known as garlic, is a species in the Onion family Alliaceae. Diphosphines are a class of compounds used as Ligands in inorganic and Organometallic chemistry. Phosphines are also a group of substituted phosphines, with the structure R₃P, where other functional groups replace hydrogens. They are important in catalysts where they complex to various metal ions; a chiral metal phosphine complex can catalyze a reaction to give chiral products. The term chiral (pronounced /ˈkaɪɹ(əl̩/ is used to describe an object that is non- superimposable on its mirror image

Phosphine is highly toxic; it kills at low concentrations. A toxin ( Greek:, toxikon, lit (poison for use on arrows is a Poisonous substance produced by living cells or organisms that is active at very low Because of this, the gas is used for pest control by fumigation. A pesticide is a substance or mixture of substances used to kill a pest. Fumigation is a method of Pest control that completely fills an area with gaseous Pesticides to suffocate or poison the pests within For farm use, it is often sold in the form of aluminium phosphide, calcium phosphide, or zinc phosphide pellets, which yield phosphine on contact with atmospheric water or rodents' stomach acid. Agriculture refers to the production of goods through the growing of plants and fungi and the raising of domesticated Animals The study of agriculture Aluminium phosphide is the Chemical compound with the formula AlP Calcium phosphide ( CP, Ca3P2 is a chemical that has uses in Incendiary bombs It has the appearance of red-brown crystalline powder or grey lumps Zinc phosphide ( Zn3[[Phosphorus P2]] is an Inorganic Chemical compound. These pellets also contain other chemicals which evolve ammonia which helps to reduce the potential for spontaneous ignition or explosion of the phosphine gas. Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Combustion or burning is a complex sequence of Exothermic chemical reactions between a Fuel and an Oxidant accompanied by the production of An explosion is a sudden increase in Volume and release of Energy in an extreme manner usually with the generation of high Temperatures and the release They may also contain other agents, such as methanethiol, to give the gas a detectable garlic smell to help warn against its presence in the atmosphere. Methanethiol (also known as methyl mercaptan) is a colorless gas with a smell like rotten Cabbage.

Phosphine is also used as a dopant in the semiconductor industry, and a precursor for the deposition of compound semiconductors. A dopant, also called doping agent and dope, is an impurity element added to a crystal or semiconductor lattice in low concentrations in order to alter the optical/electrical A semiconductor' is a Solid material that has Electrical conductivity in between a conductor and an insulator; it can vary over that A Compound Semiconductor is a Semiconductor Compound composed of elements from two or more different groups of the Periodic table. Recently high purity tertiary butyl phosphine (TBP) has been developed as a less hazardous liquid alternative to highly toxic phosphine gas, for application in Metalorganic Vapor Phase Epitaxy (MOVPE) of III-V compound semiconductors. Metalorganic vapour phase epitaxy (MOVPE is a Chemical vapour deposition method of epitaxial growth of materials especially Compound semiconductors from A Compound Semiconductor is a Semiconductor Compound composed of elements from two or more different groups of the Periodic table. Alternatively phosphine can be packaged in a cylinder containing a solid microporous adsorbent at 0 PSIG. The system is called a sub-atmospheric gas source. This type of packaging permits the gas to be stored without pressure which significantly reduces the risk of a phosphine gas leak from the cylinder. The system is able to deliver gas by applying vacuum to the cylinder valve outlet. For semiconductor manufacturing this is very practical as these processes usually operate at very high vacuum.

Phosphine is probably a normally occurring constituent of the atmosphere at very low and highly variable concentrations and hence may contribute to the global phosphorus biochemical cycle^[1]. The origin(s) of atmospheric phosphine is not certain. Possible sources include bacterial reduction of phosphate in decaying organic matter, although this is not thermodynamically favorable, and processes related to corrosion of metals containing phosphorus impurities. ^[2]

History

Perhaps because of its strong association with elemental phosphorus, phosphine was once regarded as a gaseous form of the element but Lavoisier (1789) recognised it as a combination of phosphorus with hydrogen by describing it as “hydruyet of phosphorus, or phosphuret of hydrogen”. Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15

Ernst von Meyer (1891) described the early history of phosphine research thus: "The discovery of phosphuretted hydrogen (PH₃) by Gengembre in 1783, and the examination of it by Pelletier (who was the first to prepare it pure), only became fruitful after Humphry Davy’s investigations; and the last-named elucidated the composition of this gas, and pointed out its analogy to ammonia, this being emphasised still more sharply by H. Sir Humphry Davy 1st Baronet FRS MRIA (17 December 1778 &ndash 29 May 1829 was a British Chemist and inventor Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Rose later on. "

Thénard (1845) used a cold trap to separate diphosphine from phosphine that had been generated from calcium phosphide, thereby demonstrating that P₂H₄ is responsible for spontaneous flammability associated with PH₃, and also for the characteristic orange/brown colour that can form on surfaces, which is a polymerisation product. Louis Jacques Thénard ( May 4, 1777 in the village of La Louptière, Aube - June 21, 1857 in Paris) was a In Vacuum applications a cold trap is a device that condenses all Vapors except the permanent gases into a liquid or solid Calcium phosphide ( CP, Ca3P2 is a chemical that has uses in Incendiary bombs It has the appearance of red-brown crystalline powder or grey lumps He considered diphosphine’s formula to be PH₂, and thus an intermediate between elemental phosphorus, the higher polymers, and phosphine. Calcium phosphide (nominally Ca₃P₂) produces more P₂H₄ than other phosphides because of the preponderance of P-P bonds in the starting material.

Structure and properties

PH₃ is a trigonal pyramidal molecule with C_3v molecular symmetry. Molecular symmetry in Chemistry describes the Symmetry present in Molecules and the classification of molecules according to their symmetry The length of the P-H bond 1. In Molecular geometry, bond length or bond distance is the average distance between nuclei of two bonded Atoms in a Molecule. 42 Å, the H-P-H bond angles are 93. An ångström or angstrom (symbol Å) (ˈɔːŋstrəm Swedish: ˈɔ̀ŋstrœm is an internationally recognized non- SI unit of length equal Molecular geometry or molecular structure is the three- Dimensional arrangement of the Atoms that constitute a Molecule. 5°. This article describes the unit of angle For other meanings see Degree. The dipole moment is 0. 58 D, which increases with substitution of methyl groups in the series: CH₃PH₂, 1. In a substitution reaction, a Functional group in a particular Chemical compound is replaced by another group In Chemistry, a methyl group is a Hydrophobic Alkyl Functional group named after Methane (4 10 D; (CH₃)₂PH, 1. 23 D; (CH₃)₃P, 1. 19 D. In contrast, the dipole moments of amines decrease with substitution, starting with ammonia, which has a dipole moment of 1. Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor 47 D. The low dipole moment and almost orthogonal bond angles lead to the conclusion that in PH₃ the P-H bonds are almost entirely pσ(P) – sσ(H) and the lone pair contributes only a little to the molecular orbitals. In Chemistry, a molecular orbital (or MO) is a region in which an Electron may be found in a Molecule. The high positive chemical shift of the P atom in³¹P NMR spectrum accords with the conclusion that the lone pair electrons occupy the 3s orbital and so are close to the P atom (Fluck, 1973). This electronic structure leads to a lack of nucleophilicity and an inability to form hydrogen bonds. In Chemistry, a nucleophile (literally nucleus lover as in nucleus and phile) is a Reagent that forms a Chemical bond to A hydrogen bond results from a Dipole-dipole force between an Electronegative atom and a Hydrogen atom bonded to Nitrogen, Oxygen

The aqueous solubility of PH₃ is slight; 0. Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. 22 mL of gas dissolve in 1 mL of water. Phosphine dissolves more readily in non-polar solvents than in water because of the non-polar P-H bonds. It acts as neither an acid nor a base in water. Proton exchange proceeds via a phosphonium (PH₄⁺) ion in acidic solutions and via PH₂^- at high pH, with equilibrium constants K_b = 4 x 10^-28 and K_z = 41. In chemistry the phosphonium Cation is a positively charged polyatomic ion with the chemical formula PH4+ resulting from Protonation of 6 x 10^-29.

Chemistry

Phosphine may be prepared in a variety of ways. ^[3] Industrially it can be made by the reaction of white phosphorus with sodium hydroxide, producing sodium hypophosphite and sodium phosphite as a by-product. Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15 Sodium hydroxide ( Na[[hydroxide OH]]) also known as Lye, caustic soda and (incorrectly according to IUPAC nomenclature Sodium hypophosphite (NaPO2H2 is the sodium salt of Hypophosphorous acid. The phosphite ion (PO33− is a Polyatomic ion with a Phosphorus central atom Alternatively the acid-catalyzed disproportioning of white phosphorus may be used, which yields phosphoric acid and phosphine. Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15 Phosphoric acid, also known as orthophosphoric acid or phosphoric(V acid, is a mineral (inorganic acid having the Chemical formula Both routes have industrial significance, with the acid route as the preferred method if further reaction of the phosphine to substituted phosphines is needed. This latter step requires purification and pressurizing. It can also be made (as described above) by the hydrolysis of a metal phosphide such as aluminium phosphide or calcium phosphide. Aluminium phosphide is the Chemical compound with the formula AlP Calcium phosphide ( CP, Ca3P2 is a chemical that has uses in Incendiary bombs It has the appearance of red-brown crystalline powder or grey lumps Pure samples of phosphine, free from P₂H₄, may be prepared using the action of potassium hydroxide on phosphonium iodide (PH₄I). Potassium hydroxide is the Inorganic compound with the formula K[[hydroxide OH]]

Phosphines

Related to PH₃ is the class of compounds commonly called phosphines. These are alkyl or aryl derivatives of phosphine, just as amines can be regarded as derivatives of ammonia. Amines are Organic compounds and Functional groups that contain a basic Nitrogen Atom with a Lone pair. Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Common examples include triphenylphosphine ((C₆H₅)₃P) and BINAP, both used as phosphine ligands in metal complexes such as Wilkinson's catalyst. Triphenylphosphine (in Europe triphenylphosphane is a common Organophosphorus compound with the formula P(C6H53 - often abbreviated to BINAP is an Acronym for the Organophosphorus compound 22'-bis(diphenylphosphino-11'-binaphthyl In Chemistry, a ligand is either an Atom, Ion, or Molecule (see also Functional group) that bonds to a central metal generally The term complex in Chemistry is usually used to describe molecules or ensembles formed by the combination of Ligands and metal Ions. Wilkinson's catalyst is the common name for chlorotris(triphenylphosphinerhodium(I, a Chemical compound with the formula RhCl(PPh33 (Ph Metal phosphine complexes are catalysts for reactions such as the Sonogashira coupling. Catalysis is the process in which the rate of a Chemical reaction is increased by means of a Chemical substance known as a catalyst In Organic chemistry, a Sonogashira coupling is a Coupling reaction of terminal Alkynes with Aryl or Vinyl halides This reaction was Most of these phosphines, with the exception of triphenyl phosphine, are made from pressurized, purified phosphine gas as described above. Triphenylphosphine (in Europe triphenylphosphane is a common Organophosphorus compound with the formula P(C6H53 - often abbreviated to

A large industrial application of phosphine is found in the production of tetrakis(hydroxymethyl) phosphonium salts, made by passing phosphine gas through a solution of formaldehyde and a mineral acid such as hydrochloric acid. In chemistry the phosphonium Cation is a positively charged polyatomic ion with the chemical formula PH4+ resulting from Protonation of Formaldehyde is a Chemical compound with the formula H2CO It is the simplest Aldehyde —an organic compound containing a terminal Carbonyl A mineral acid is an Acid derived by Chemical reaction from inorganic Minerals as opposed to Organic acids These have Hydrogen Hydrochloric acid is the Solution of Hydrogen chloride ( H[[Chlorine Cl]] in water These find application as flame retardants for textile ("Proban(r) - registered trademark of Rhodia UK Limited") and as biocides. Flame retardants are materials that inhibit or resist the spread of Fire. A biocide is a Chemical substance capable of killing living organisms, usually in a selective way

Phosphine is often confused with phosgene, (COCl₂) which has a similar-sounding name but contains no phosphorus. Phosgene is the Chemical compound with the formula COCl2 This colorless gas gained infamy as a Chemical weapon during World War I

Use as a fumigant

Phosphine is highly toxic to organisms undergoing oxidative respiration, but is non toxic to organisms kept under low oxygen (<1%) or that can anaerobically respire (i. Oxidative phosphorylation is a Metabolic pathway that uses energy released by the oxidation of Nutrients to produce Adenosine triphosphate (ATP e. ferment). Fermentation is the process of deriving energy from the oxidation of organic compounds such as carbohydrates using an endogenous electron acceptor which is Because of these characteristics, phosphine is widely used as a fumigant of metabolically dormant stored products such as grain. Fumigation is a method of Pest control that completely fills an area with gaseous Pesticides to suffocate or poison the pests within Dormancy is a period in an organism's life cycle when growth development and (in animals physical activity is temporarily suspended The toxicity of phosphine kills insect pests that might infest the grain, but does not affect the viability of the dormant grain.

Because continued use of the previously widely used fumigant methyl bromide has been banned under the Montreal Protocol, phosphine is the only widely used, cost effective, rapidly acting fumigant that does not leave residues on the stored product. Fumigation is a method of Pest control that completely fills an area with gaseous Pesticides to suffocate or poison the pests within The Chemical compound bromomethane, commonly known as methyl bromide, is an organic Halogen compound with formula C[[Hydrogen For other similarly-named agreements see Montreal Convention (disambiguation. Given the heavy reliance on phosphine as a means of protecting grain from insect infestation, it is disturbing to note that pests developing high levels of resistance toward phosphine have become commonplace in many countries of Asia and in Australia as well. Active research in Australia into the mode of action of phosphine and the mechanisms whereby insects acquire resistance is being carried out by the CSIRO in Canberra, QDPI&F in Queensland and the University of Queensland. The Commonwealth Scientific and Industrial Research Organisation ( CSIRO) is the national government body for scientific research in Australia. The University of Queensland (UQ is one of Australia's premier learning and research institutions

See also

• Phosphine oxide - OPR₃
• Phosphinite - P(OR)R₂
• Phosphonite - P(OR)₂R
• Phosphite - P(OR)₃
• Phosphinate - OP(OR)R₂
• Phosphonate - OP(OR)₂R
• Phosphate - OP(OR)₃

References

External links

• International Chemical Safety Card 0694