P

Phosphoric acid

IUPAC: phosphoric acid

H3PO4 Acids CAS 7664-38-2
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Quick Reference
Formula / NotationH3PO4
CAS Number7664-38-2
Molecular Weight97.995
Melting Point108 °F (NIOSH, 2024)
Boiling Pointgreater than 266 °F at 760 mmHg (USCG, 1999)
Density1.892 at 77 °F (USCG, 1999) - Denser than water; will sink
SolubilityMiscible (NIOSH, 2024)
AppearancePhosphoric acid appears as a clear colorless liquid or transparent crystalline solid. The pure solid melts at 42.35 °C and has a density of 1.834 g / cm3. Liquid is usually an 85% aqueous solution...
Also Known As7664-38-2; ORTHOPHOSPHORIC ACID; o-Phosphoric acid; Wc-reiniger; Acidum phosphoricum; Sonac; Phosphorsaeure; Evits; Acide phosphorique; Phosphoricum acidum
CategoryAcids

What is Phosphoric acid?

Phosphoric acid is a phosphorus oxoacid that consists of one oxo and three hydroxy groups joined covalently to a central phosphorus atom. It has a role as a NMR chemical shift reference compound, a fertilizer, a solvent, a human metabolite and an algal metabolite. It is a conjugate acid of a phosphate ion and a dihydrogenphosphate.

Formula & Notation

H3PO4

IUPAC Name: phosphoric acid

Other Names / Synonyms: 7664-38-2; ORTHOPHOSPHORIC ACID; o-Phosphoric acid; Wc-reiniger; Acidum phosphoricum; Sonac; Phosphorsaeure; Evits; Acide phosphorique; Phosphoricum acidum

Properties & Characteristics

Appearance: Phosphoric acid appears as a clear colorless liquid or transparent crystalline solid. The pure solid melts at 42.35 °C and has a density of 1.834 g / cm3. Liquid is usually an 85% aqueous solution.... Molecular formula: H3O4P. Molecular weight: 97.995 g/mol. Boiling point: greater than 266 °F at 760 mmHg (USCG, 1999). Melting point: 108 °F (NIOSH, 2024). Density: 1.892 at 77 °F (USCG, 1999) - Denser than water; will sink. Solubility: Miscible (NIOSH, 2024). Vapor pressure: 0.03 mmHg (NIOSH, 2024). LogP: -2.1.

Physical Data

PropertyValue
Melting Point108 °F (NIOSH, 2024)
Boiling Pointgreater than 266 °F at 760 mmHg (USCG, 1999)
Density1.892 at 77 °F (USCG, 1999) - Denser than water; will sink
Molecular Weight97.995
SolubilityMiscible (NIOSH, 2024)
AppearancePhosphoric acid appears as a clear colorless liquid or transparent crystalline solid. The pure solid melts at 42.35 °C and has a density of 1.834 g / cm3. Liquid is usually an 85% aqueous solution...

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 Phosphoric acid
Formula H3PO4
CAS Number 7664-38-2
Molecular Weight 97.995
Category Acids
Synonyms 7664-38-2; ORTHOPHOSPHORIC ACID; o-Phosphoric acid; Wc-reiniger; Acidum phosphoricum; Sonac; Phosphorsaeure; Evits; Acide phosphorique; Phosphoricum acidum

Frequently Asked Questions

Phosphoric acid is a phosphorus oxoacid that consists of one oxo and three hydroxy groups joined covalently to a central phosphorus atom. It has a role as a NMR chemical shift reference compound, a fertilizer, a solvent, a human metabolite and an algal metabolite. It is a conjugate acid of a phosphate ion and a dihydrogenphosphate.

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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.