Hypophosphorous acid

Hypophosphorous acid[1]
Wireframe model of hypophosphorous acid
Wireframe model of hypophosphorous acid
Names
IUPAC name
Phosphinic acid
Other names
Hydroxy(oxo)-λ5-phosphane

Hydroxy-λ5-phosphanone
Oxo-λ5-phosphanol
Oxo-λ5-phosphinous acid

Phosphonous acid (for minor tautomer)
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.026.001 Edit this at Wikidata
KEGG
UNII
UN number UN 3264
  • InChI=1S/H3O2P/c1-3-2/h3H2,(H,1,2) checkY
    Key: ACVYVLVWPXVTIT-UHFFFAOYSA-N checkY
  • InChI=1/H3O2P/c1-3-2/h3H2,(H,1,2)
    Key: ACVYVLVWPXVTIT-UHFFFAOYAQ
  • O[PH2]=O
Properties
H3PO2
Molar mass 66.00 g/mol
Appearance colorless, deliquescent crystals or oily liquid
Density 1.493 g/cm3[2]

1.22 g/cm3 (50 wt% aq. solution)

Melting point 26.5 °C (79.7 °F; 299.6 K)
Boiling point 130 °C (266 °F; 403 K) decomposes
miscible
Solubility very soluble in alcohol, ether
Acidity (pKa) 1.2
Conjugate base Phosphinate
Structure
pseudo-tetrahedral
Hazards
Flash point Non-flammable
Safety data sheet (SDS) JT Baker
Related compounds
Phosphorous acid
Phosphoric acid
Related compounds
Sodium hypophosphite
Barium hypophosphite
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Hypophosphorous acid (HPA), or phosphinic acid, is a phosphorus oxyacid and a powerful reducing agent with molecular formula H3PO2. It is a colorless low-melting compound, which is soluble in water, dioxane and alcohols. The formula for this acid is generally written H3PO2, but a more descriptive presentation is HOP(O)H2, which highlights its monoprotic character. Salts derived from this acid are called hypophosphites.[3]

HOP(O)H2 exists in equilibrium with the minor tautomer HP(OH)2. Sometimes the minor tautomer is called hypophosphorous acid and the major tautomer is called phosphinic acid.

  1. ^ Petrucci, Ralph H. (2007). General Chemistry (9th ed.). p. 946.
  2. ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  3. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.