What does phosphite mean?
A phosphite is a chemical substance related to phosphorous acid. Its central form is the phosphite ion, PO₃³⁻, in which phosphorus has the +3 oxidation state; salts of this ion include sodium phosphite and potassium phosphite. Phosphites are chemically important as reducing agents and can be oxidized to phosphates, whose phosphorus has the +5 oxidation state. In food processing, some phosphites are used as stabilizers or acidity regulators, including under the European food-additive designation E450. The word also appears in organic chemistry, where phosphite groups and phosphite esters participate in reactions involving phosphorus. Although its name may suggest a close relationship with phosphate, the two belong to distinct oxidation states and have different chemical properties. The term is therefore primarily technical and is encountered in chemistry, industrial processing, and food-science contexts rather than in ordinary conversation.
nounA phosphite is a compound or ion derived from phosphorous acid, typically containing the phosphite ion, PO₃³⁻, or a related phosphorus-containing group. In chemistry, phosphites are distinguished from phosphates, which contain phosphorus in a higher oxidation state.
- A phosphite ion or compound derived from phosphorous acid, especially one containing phosphorus in the +3 oxidation state.
- In some chemical nomenclature, a phosphite ester or related phosphorus compound containing a phosphite group.
"Sodium phosphite is used in some industrial processes as a reducing agent."
"The phosphite ion is a reducing agent and can be oxidized to phosphate."
"The manufacturer lists sodium phosphite as an acidity regulator in the processed food."
The plural is used when referring to multiple phosphite compounds or phosphite groups.
"Several phosphites are used as additives in food processing."
Phosphite is the less oxidized, more reactive side of the phosphorus family, sitting between phosphide and phosphate.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does phosphite come from?
The word was formed in the 19th century from the phosphorus root and the chemical suffix -ite, which is used in names for compounds and ions. Its name reflects its relationship to phosphorous acid, from which phosphites derive. The related terms phosphide, phosphine, phosphate, and phosphonate belong to the same broader family of phosphorus and phosphorous derivatives.
How phosphite is actually used
In technical chemistry, the term is used for phosphorus-containing ions, salts, and related compounds, so the precise structure may depend on context. It should not be confused with phosphite in the informal sense of a phosphor bronze component, which is a separate and obsolete usage.
Easily confused with phosphite
A phosphite contains phosphorus in the +3 oxidation state, whereas a phosphate contains phosphorus in the +5 oxidation state.
A phosphide is a binary compound containing phosphorus and a more electropositive element, while a phosphite is derived from phosphorous acid or contains a phosphite group.