Phosphite

Phosphite

Names
Systematic IUPAC name Phosphite
Identifiers
CAS Number	14901-63-4 N
3D model (Jmol)	Interactive image Interactive image
ChEBI	CHEBI:45064 N
ChEMBL	ChEMBL1235376 N
ChemSpider	97035 N
Gmelin Reference	68617
MeSH	Phosphorite
PubChem	107908
InChI InChI=1S/O3P/c1-4(2)3/q-3 N Key: AQSJGOWTSHOLKH-UHFFFAOYSA-N N
SMILES [O-]P([O-])[O-] P([O-])([O-])[O-]
Properties
Chemical formula	PO3− 3
Molar mass	78.9720 g mol−1
Related compounds
Other anions	Phosphinite Phosphonite
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Phosphonite

A phosphite in inorganic chemistry is a salt of phosphorous acid, H₃PO₃ and following the IUPAC naming recommendations the phosphite ion would be PO3−
3, a salt of P(OH)₃.

Historically phosphite has referred to salts containing HPO2−
3 and this is because aqueous H₃PO₃ is not triprotic P(OH)₃ but almost exclusively the diprotic HP(O)(OH)₂ (IUPAC recommended name of phosphonic acid). The IUPAC-recommended name for the HPO2−
3 ion is phosphonate and 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. A well-known university-level textbook follows the IUPAC recommendations. 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 mean phosphite ester, an organophosphorus compound with the formula P(OR)₃.

Salts containing PO3−
3 cannot be isolated from aqueous solutions of phosphorous acid. Only salts containing H
2PO−
3 or HPO2−
3 are produced. There are reports of a salt Na₃PO₃ in older literature and the use of sodium metal to remove the third hydrogen in H₃PO₃ is mentioned in a textbook. However, if PO3−
3 is produced in aqueous solution or dissolved it would form H
2PO−
3 or HPO2−
3 immediately. Na₃PO₃ is referred to in many textbooks on Internet sources, often as part of an exercise in naming inorganic compounds, but also as a misprint of the formula for the phosphate salt, Na₃PO₄.