P

Phosphorous acid

IUPAC: phosphorous acid

H3PO3 Acids CAS 10294-56-1
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Quick Reference
Formula / NotationH3PO3
CAS Number10294-56-1
Molecular Weight81.996
AppearancePellets or Large Crystals; Dry Powder; Liquid
Also Known As10294-56-1; Orthophosphorus acid; DTXSID7035511; CHEBI:36361; RefChem:1095536; DTXCID5015511; 233-663-1; 35V6A8JW8E; Dihydroxyphosphine oxide; Trihydroxyphosphine
CategoryAcids

What is Phosphorous acid?

Phosphorous acid is a phosphorus oxoacid. It is a conjugate acid of a dihydrogenphosphite. It is a tautomer of a phosphonic acid.

Formula & Notation

H3PO3

IUPAC Name: phosphorous acid

Other Names / Synonyms: 10294-56-1; Orthophosphorus acid; DTXSID7035511; CHEBI:36361; RefChem:1095536; DTXCID5015511; 233-663-1; 35V6A8JW8E; Dihydroxyphosphine oxide; Trihydroxyphosphine

Properties & Characteristics

Appearance: Pellets or Large Crystals; Dry Powder; Liquid. Molecular formula: H3O3P. Molecular weight: 81.996 g/mol. LogP: -1.5.

Physical Data

PropertyValue
Molecular Weight81.996
AppearancePellets or Large Crystals; Dry Powder; Liquid

Uses & Applications

Used in industrial chemical synthesis, fertilizer production, battery electrolytes, metal processing, and laboratory acid-base reactions.

Safety Information

Corrosive. Causes severe burns to skin, eyes, and respiratory tract. Wear appropriate PPE including gloves, goggles, and lab coat. Consult SDS before use.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Phosphorous acid
Formula H3PO3
CAS Number 10294-56-1
Molecular Weight 81.996
Category Acids
Synonyms 10294-56-1; Orthophosphorus acid; DTXSID7035511; CHEBI:36361; RefChem:1095536; DTXCID5015511; 233-663-1; 35V6A8JW8E; Dihydroxyphosphine oxide; Trihydroxyphosphine

Frequently Asked Questions

Phosphorous acid is a phosphorus oxoacid. It is a conjugate acid of a dihydrogenphosphite. It is a tautomer of a phosphonic acid.

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Editorial standards: Chemical data is sourced from peer-reviewed literature, CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA, and IAEA. For educational purposes only — always consult official SDS documentation and qualified professionals before handling chemicals.