PhosphiteAphosphitein inorganic chemistry is a salt ofphosphorous acid, H3PO3and following the IUPAC naming recommendations the phosphite ion would be PO33[2]a salt of P(OH)3.Historically phosphite has referred to salts containing HPO32and this is because aqueous H3PO3is not triprotic P(OH)3but almost exclusively the diprotic HP(O)(OH)2(IUPAC recommended name ofphosphonic acid). The IUPAC recommended name for the HPO32ion isphosphonateand this naming convention is becoming more common. In the US the IUPAC naming conventions for inorganic compounds are taught at high school, but not as a 'required' part of the curriculum.[3]A well known university level text book follows the IUPAC recommendations.[4]In practise any reference to "phosphite" should be investigated carefully to determine which naming convention is being employed.The term phosphite is also used to meanphosphite ester, anorganophosphoruscompound with the formula P(OR)3.Phosphite

Names

Systematic IUPAC namePhosphite[1]

Identifiers

CAS Registry Number14901-63-4

ChEBICHEBI:45064

ChEMBLChEMBL1235376

ChemSpider97035

Gmelin Reference68617

InChI[show]

Jmol-3D imagesImageImage

MeSHPhosphorite

PubChem107908

SMILES[show]

Properties

Chemical formulaPO33

Molar mass78.9720 g mol1

Related compounds

OtheranionsPhosphinite

Phosphonite

Except where otherwise noted, data are given for materials in theirstandard state(at 25C [77F], 100kPa).

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Infoboxreferences

Salts containing phosphite, PO33[edit]Salts containing PO33cannot be isolated from aqueous solutions of phosphorous acid. Only salts containing H2PO3or HPO32are produced. There are reports of a salt Na3PO3in older literature[5]and the use of sodium metal to remove the third hydrogen in H3PO3is mentioned in a text book.[4]However if PO33is produced in aqueous solution or dissolved it would form H2PO3or HPO32immediately.[4]Na3PO3is referred to in many text books on internet sources, often as part of an exercise in naming inorganic compounds, but also as a misprint of the formula for thephosphatesalt,Na3PO4.In contrast to the poor evidence for the existence of PO33the corresponding arsenic ion, ortho-arsenite, AsO33is known, and an example is Ag3AsO3as well as the polymeric meta-arsenite [AsO2]n.[6]The iso-electronicsulfiteion, SO32is known from its salts.[6]Salts containing HPO32called phosphonates or phosphites[edit]Many salts containing this ion are known, and many have been investigated structurally, these include (NH4)2HPO3.H2O, CuHPO3.H2O, SnHPO3and Al2(HPO3)3.4H2O.[7]The structure of the HPO32is approximately tetrahedral.[8][9]HPO32has a number of canonical resonance forms making it isoelectronic withbisulfiteion, HSO3, which has a similar structure,[6]

Salts containing HP(O)2OHcalled hydrogenphosphonates or acid phosphites[edit]Acid or hydrogen phosphites (which the IUPAC recommends be called hydrogenphosphonates), containing the ion HP(O)2OHsuch as NH4HP(O)2OH, can be prepared.[6]Hydrogen bonding between anions leads to polymeric anionic structures.[9]Recently some others, RbHPHO3, CsHPHO3, TlHPHO3have been prepared by reactingphosphorous acidwith the metalcarbonate. These compounds contain a layer polymeric anion consisting of HPO3tetrahedra linked by hydrogen bonds. These layers are interleaved by layers of metal cations.[10]Salts containing H2P2O52called diphosphites or pyrophosphites[edit]Pyrophosphites (diphosphites) can be produced by gently heating acid phosphites under reduced pressure. They contain the ion, H2P2O52which can be formulated [HP(O)2OP(O)2H]2.[6][9]Synthesis of phosphite esters[edit]Organophosphorus compoundscalledphosphite esters(or sometimes just phosphites) have the formula (RO)3P. They are prepared by reactingphosphorus trichloride(orphosphorus tribromide) with analcoholand a tertiaryamine.PCl3+ 3 ROH + 3 R'3N P(OR)3+ 3R'3NHClUse as fungicides[edit]Inorganic phosphites (containing HPO32) have been applied to crops to combat fungus-like pathogens of the orderOomycetes. The situation is confusing because of the similarity in name between phosphite andphosphate(a major plantnutrientandfertilizeringredient), and controversial because phosphites have sometimes been advertised as fertilizers, even though they are converted to phosphate too slowly to serve as a plant's main phosphorus source. Lemoynie[11]and others[12]have described this complicated situation and noted that calling phosphites fertilizers avoided the regulatory complication and negative public perceptions that might have been incurred by registering them as fungicides.See also[edit] Hypophosphite- H2PO2 Organophosphorus Phosphine- PH3and the organic phosphines PR3 Phosphine oxide- OPR3 Phosphinite- P(OR)R2 Phosphonite- P(OR)2R Phosphinate- OP(OR)R2 Phosphonate- organic phosphonates OP(OR)2R Phosphate- PO43 organophosphate- OP(OR)3Further reading[edit] A. Earnshaw, Norman Greenwood (1997).The Chemistry of the Elements - Second Edition. pp.513514.References[edit]1. Jump up^"Phosphorite - PubChem Public Chemical Database".The PubChem Project. USA: National Center for Biotechnology Information.2. Jump up^NOMENCLATURE OF INORGANIC CHEMISTRY IUPAC Recommendations 2005 ed. N. G. Connelly et al. RSC Publishinghttp://www.chem.qmul.ac.uk/iupac/bioinorg/3. Jump up^Physical setting/ chemistry core curriculum, The University of the State of New York, The State Education Department,http://www.p12.nysed.gov/ciai/mst/pub/chemist.pdf4. ^Jump up to:abcEgon Wiberg, Arnold Frederick Holleman (2001)Inorganic Chemistry, ElsevierISBN 01235265155. Jump up^Modern Inorganic Chemistry, Joseph Mellor, Longmans, Green and Company, 19176. ^Jump up to:abcdeGreenwood, Norman N.; Earnshaw, Alan (1997).Chemistry of the Elements(2nd ed.).Butterworth-Heinemann.ISBN0080379419.7. Jump up^Synthesis and crystal structures of aluminum and iron phosphites, D.M. Poojary, Y. Zhang, D.E. Cox, P.R. Rudolf, S. Cheng & A. Clearfield,J. Chem. Crystallogr. 24 (1994) 155-1638. Jump up^L. E. Gordon, W. T. A. Harrison (February 2003). "Bis(melaminium) hydrogen phosphite tetrahydrate". Acta Cryst. 59 (2): o195-o197.doi:10.1107/S16005368030012479. ^Jump up to:abcCrystal chemistry of inorganic phosphites, J. Loub, Acta Cryst. (1991), B47, 468-473,doi:10.1107/S010876819100238010. Jump up^Kosterina, E. V., Troyanov, S. I., Kemnitz, E. & Aslanov, L. A. (2001). "Synthesis and Crystal Structure of Acid Phosphites RbH2PO3, CsH2PO3, and TlH2PO3".Russian Journal of Coordination Chemistry27(7): 458462.doi:10.1023/A:1011377229855.11. Jump up^Phosphites and Phosphates: When Distributors and Growers alike could get confused! by Jean-Pierre Leymonie. Courtesy of New Ag International, September 2007 edition.12. Jump up^Thao; Yamakawa (2008).Soil Science and Plant Nutrition55: 228234.doi:10.1111/j.1747-0765.2009.00365.x.Missing or empty|title=(help)