Pyrophosphoric acid

A summary of the most common chemical descriptors (InChI Key and SMILES codes) for Pyrophosphoric acid are summarized together with 3D and 2D structures and relevant physico-chemical properties.

What is the Pyrophosphoric acid?

The molecule Pyrophosphoric acid presents a molecular formula of H4O7P2 and its IUPAC name is phosphono dihydrogen phosphate.

Pyrophosphoric acid is a phosphorus oxoacid and an inorganic phosphate. It has the chemical formula H4P2O7. The molecule consists of two phosphorus atoms bonded to each other by a double bond, with each phosphorus atom bonded to three oxygen atoms. The acidity of pyrophosphoric acid is due to the presence of the phosphorus-oxygen double bond. This double bond is also responsible for the molecule's high melting and boiling points..

Pyrophosphoric acid is used as a reagent in organic synthesis and as a catalyst in the production of phosphate esters. It is also used as a corrosion inhibitor in metalworking fluids..

3D structure

Cartesian coordinates

Geometry of Pyrophosphoric acid in x, y and z coordinates (Å units) to copy/paste elsewhere. Generated with Open Babel software.

2D drawing


Pyrophosphoric acid XPPKVPWEQAFLFU-UHFFFAOYSA-N chemical compound 2D structure molecule svg
Pyrophosphoric acid


Molecule descriptors

IUPAC namephosphono dihydrogen phosphate
InChI codeInChI=1S/H4O7P2/c1-8(2,3)7-9(4,5)6/h(H2,1,2,3)(H2,4,5,6)

Other names (synonyms)

IUPAC nomenclature provides a standardized method for naming chemical compounds. Although this system is widely used in chemistry, many chemical compounds have also other names commonly used in different contexts. These synonyms can come from a variety of sources and are used for a variety of purposes.

One common source of synonyms for chemical compounds is the common or trivial names, assigned on the basis of appearance, properties, or origin of the molecule.

Another source of synonyms are historical or obsolete names employed in the past, however replaced nowadays by more modern or standardized names.

In addition to common and historical names, chemical compounds may also have synonyms that are specific to a particular field or industry.

  • (4-)Diphosphoric acid ion
  • (P2O74-)Diphosphate
  • (phosphonooxy)phosphonic acid
  • 1,5-dihydrido-2,4-dihydroxido-2,4-dioxido-1,3,5-trioxy-2,4-diphosphy-[5]catena
  • 2466-09-3
  • 2CB62164-1ACF-40BE-BF6A-880D0A00850A
  • 33943-49-6
  • 4E862E7GRQ
  • BDBM50147591
  • C00013
  • CAA46609
  • CCG-37688
  • CS-0030756
  • DB04160
  • Diphosphoric acid
  • Diphosphorsaeure
  • FT-0652670
  • GTPL3151
  • H4P2O7
  • J-015622
  • L000488
  • MFCD00011343
  • NCGC00013687
  • NCGC00013687-02
  • NCGC00013687-03
  • NCGC00096798-01
  • NCI56751
  • NCI60_004388
  • NCIStruc1_000506
  • NCIStruc2_000426
  • NSC-289196
  • NSC289196
  • Oxy-1,1-diphosphonic acid
  • P00025
  • PPV
  • Phosphonooxyphosphonic acid
  • Pyrophosphoric acid
  • Pyrophosphoric acid, syrupy
  • Pyrophosphorsaeure
  • Q411092
  • [(HO)2P(O)OP(O)(OH)2]
  • acide diphosphorique
  • mu-oxido-bis(dihydroxidooxidophosphorus)
  • phosphono dihydrogen phosphate
  • pyrophosphate TMS4

Reference codes for other databases

There exist several different chemical codes commonly used in orded to identify molecules:
  • ZINC6827695
  • UNII-4E862E7GRQ
  • AKOS015856732
  • DTXSID4075035
  • CHEMBL1160571
  • CHEBI:29888
  • EINECS 219-574-0

Physico-Chemical properties

IUPAC namephosphono dihydrogen phosphate
Molecular formulaH4O7P2
Molecular weight177.975
Melting point (ºC)
Boiling point (ºC)
Density (g/cm3)
Molar refractivity25.17
Topological polar surface area143.9

LogP and topological polar surface area (TPSA) values were estimated using Open Babel software.

The n-octanol/water partition coeficient (Kow) data is applied in toxicology and drug research. Kow values are used, to guess the environmental fate of persistent organic pollutants. High partition coefficients values, tend to accumulate in the fatty tissue of organisms. Molecules with a log(Kow) (or LogP) greater than 5 are considered to bioaccumulate.

TPSA values are the sum of the surface area over all polar atoms or molecules, mainly oxygen and nitrogen, also including hydrogen atoms.

In medicinal chemistry, TPSA is used to assess the ability of a drug to permeabilise cells.

For molecules to penetrate the blood-brain barrier (and act on receptors in the central nervous system), TPSA values below 90 Å2 are required. Thus, molecules with a polar surface area greater than 140 Å2 tend to be poorly permeable to cell membranes.