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Phosphoric acid

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Names IUPAC name
Phosphoric acid
Other names
Orthophosphoric acid, hydrogen phosphate
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard100.028.758EC Number
  • 231-633-2
E numberE338 (antioxidants, ...)2000 KEGG
RTECS number
  • TB6300000
UNII
UN number1805
  • InChI=1S/H3O4P/c1-5(2,3)4/h(H3,1,2,3,4)
    Key: NBIIXXVUZAFLBC-UHFFFAOYSA-N
  • InChI=1/H3O4P/c1-5(2,3)4/h(H3,1,2,3,4)
    Key: NBIIXXVUZAFLBC-UHFFFAOYAI
  • OP(=O)(O)O
Properties H3PO4Molar mass97.994 g·mol Appearance Colorless solid OdorOdorless Density1.6845 g/cm (25 °C, 85%), 1.834 g/cm (solid) Melting point42.35 °C (108.23 °F; 315.50 K) anhydrous
29.32 °C (84.78 °F; 302.47 K) hemihydrateBoiling point
  • 100 °C (212 °F) (only water evaporates)
  • 392.2 g/(100 g) (−16.3 °C)
  • 369.4g/(100 mL) (0.5 °C)
  • 446 g/(100 mL) (15 °C)
  • 548g/(100 mL) (20 °C)
SolubilitySoluble in ethanollog P−2.15 Vapor pressure0.03mmHg (20°C) Conjugate baseDihydrogen phosphate−43.8·10cm/mol
  • 1.3420 (8.8% w/w aq. soln.)
  • 1.4320 (85% aq. soln) 25 °C
Viscosity2.4–9.4cP (85% aq. soln.)
147 cP (100%) Structure Monoclinic Tetrahedral Thermochemistry 145.0 J/(mol⋅K) 150.8 J/(mol⋅K) −1271.7 kJ/mol −1123.6 kJ/mol Hazards GHS labelling: DangerH290, H314P280, P305+P351+P338, P310NFPA 704 (fire diamond)
3
0
0
Flash pointNon-flammable Lethal dose or concentration (LD, LC): 1530 mg/kg (rat, oral) NIOSH (US health exposure limits):
PEL (Permissible)
TWA 1 mg/m
REL (Recommended)
TWA 1 mg/m ST 3 mg/m
IDLH (Immediate danger)
1000 mg/m Safety data sheet (SDS) ICSC 1008Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formulaH3PO4. It is commonly encountered as an 85% aqueous solution, which is a colourless, odourless, and non-volatile syrupy liquid. It is a major industrial chemical, being a component of many fertilizers.

The compound is an acid. Removal of all three H ions gives the phosphate ion PO3−4. Removal of one or two protons gives dihydrogen phosphate ion H2PO−4, and the hydrogen phosphate ion HPO2−4, respectively. Phosphoric acid forms esters, called organophosphates.

The name "orthophosphoric acid" can be used to distinguish this specific acid from other "phosphoric acids", such as pyrophosphoric acid. Nevertheless, the term "phosphoric acid" often means this specific compound; and that is the current IUPAC nomenclature.

Wikipedia source