Phosphorus trioxide: Difference between revisions

| verifiedrevid = 444052346

| Name = Phosphorus trioxide

| ImageFile = Phosphorus-trioxide-from-xtal-3D-balls.png

| ImageName = Ball-and-stick model of the P4O6 molecule

| ImageFile1 = Phosphorus-trioxide-xtal-3D-balls-A.png

| ImageName1 = Packing of P4O6 molecules in the crystal structure

| OtherNames = Phosphorus(III) oxide,<br />Phosphorus [[sesquioxide]],<br />Phosphorous oxide,<br />Phosphorous anhydride

| Section1 = {{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChEBI_Ref = {{ebicite|correct|EBI}}

| ChEBI = 37372

| SMILES = O1P3OP2OP(OP1O2)O3

| CASNo = 1314-24-5

| PubChem = 123290

| Section2 = {{Chembox Properties

| Formula = P₄O₆

| MolarMass = 219.88 g mol⁻¹

| Appearance = colourless monoclinic crystals or liquid

| Density = 2.135 g/cm³

| Solubility = reacts

| MeltingPt = 23.8 °C

| BoilingPt = 173.1 °C

| pKa = 9.2

| pKb =

| Section3 = {{Chembox Structure

| MolShape = '''See Text'''

| CrystalStruct =

| Dipole = 0

| Section4 = {{Chembox Thermochemistry

| DeltaHf =

| Entropy =

}}

| Section5 = {{Chembox Pharmacology

| ProteinBound =}}

| Section7 = {{Chembox Hazards

| ExternalMSDS =

| EUClass =

| NFPA-H =

| NFPA-F =

| NFPA-R =

| RPhrases =

| SPhrases =

}}

| Section8 = {{Chembox Related

| OtherAnions = [[Phosphorus trisulfide]]

| OtherCations = [[Dinitrogen trioxide]]<br />[[Arsenic trioxide]]<br />[[Antimony trioxide]]

| OtherCpds = [[Phosphorus pentoxide]]<br />[[Phosphorous acid]]

'''Phosphorus trioxide''' is the [[chemical compound]] with the molecular formula P₄O₆. Although it should properly be named tetraphosphorus hexoxide, the name phosphorus trioxide preceded the knowledge of the compound's molecular structure, and its usage continues today. This colorless solid is structurally related to [[adamantane]]. It is formally the [[anhydride]] of [[phosphorous acid]], H₃PO₃, but cannot be obtained by the dehydration of the acid. It is a white, waxy, crystalline and highly toxic solid<ref name = "Wiberg&Holleman">{{cite book |author=A. F. Holleman; Wiberg, Egon; Wiberg, Nils |title=Inorganic Chemistry |publisher=Academic Press |location=Boston |year=2001 |pages= |isbn=0-12-352651-5 |oclc= |doi= |accessdate=}}</ref> and has an odor similar to that of garlic.{{citation needed|date=October 2010}}

It is obtained by the combustion of phosphorus in a limited supply of air at low temperature.

:P₄(s) + 3 O₂(g) → P₄O₆(s)

== Chemical Properties ==

Phosphorus trioxide reacts with cold water to form phosphorous acid.

: P₄O₆(s) + 6 H₂O(l) → 4 H₃PO₃(aq)

It reacts vigorously with hot water, via a complex set of reactions, to form [[Allotropes of phosphorus#Red phosphorus|red phosphorus]], [[phosphines]], H₃PO₃ and [[phosphoric acid|H₃PO₄]].

P₄O₆ reacts with [[hydrogen chloride]] to form H₃PO₃ and [[phosphorus trichloride]].

With chlorine or bromine it forms the corresponding [[Phosphorus chlorides#Oxyhalides and thiohalides|phosphoryl halide]], and it reacts with iodine in a sealed tube to from [[diphosphorus tetraiodide]].<ref name = "Wiberg&Holleman" />

P₄O₆ is a ligand for transition metals, comparable to [[phosphite]]. Tetracarbonyl(tetraphosphorus hexaoxide)iron, P₄O₆·Fe(CO)₄, is an example of a complex containing the phosphorus trioxide cage as a ligand. Its molecular structure as determined by single-crystal X-ray diffraction<ref>{{ cite journal | journal = Acta Cryst. | volume = C52 | issue = 11 | month = November | year = 1996 | pages = 2650–2652 | doi = 10.1107/S0108270196004398 | title = Tetracarbonyl(tetraphosphorus hexaoxide)iron | author = M. Jansen and J. Clade }}</ref> is shown below:

[[File:Tetraphosphorus-hexaoxide-iron-tetracarbonyl-complex-from-xtal-3D-balls.png|100px]]

[[Category:Inorganic phosphorus compounds]]

[[cs:Oxid fosforitý]]

[[de:Phosphortrioxid]]

[[es:Óxido de fósforo (III)]]

[[it:Anidride fosforosa]]

[[hu:Foszfor-trioxid]]

[[nl:Difosfortrioxide]]

[[pt:Trióxido de fósforo]]

[[simple:Phosphorus(III) oxide]]

[[sv:Fosfortrioxid]]

[[zh:三氧化二磷]]