Disulfuric acid

Disulfuric acid
Ball and stick model of the disulfuric acid molecule
Names
IUPAC name
Disulfuric acid [1]
Other names
Pyrosulfuric acid, Oleum
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.029.069 Edit this at Wikidata
EC Number
  • 231-976-8
MeSH Pyrosulfuric+acid
UNII
  • InChI=1S/H2O7S2/c1-8(2,3)7-9(4,5)6/h(H,1,2,3)(H,4,5,6) checkY
    Key: VFNGKCDDZUSWLR-UHFFFAOYSA-N checkY
  • InChI=1/H2O7S2/c1-8(2,3)7-9(4,5)6/h(H,1,2,3)(H,4,5,6)
    Key: VFNGKCDDZUSWLR-UHFFFAOYAZ
  • OS(=O)(=O)OS(O)(=O)=O
  • OS(=O)(=O)OS(=O)(=O)O
  • O=S(=O)(O)OS(=O)(=O)O
Properties
H2O7S2
Molar mass 178.13 g·mol−1
Appearance colorless
Melting point 36 °C (97 °F; 309 K)
Acidity (pKa) 2.5 (20 °C; in conc. H2SO4)[2]
Conjugate base Disulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Disulfuric acid (alternative spelling disulphuric acid) or pyrosulfuric acid (alternative spelling pyrosulphuric acid), also named oleum, is a sulfur oxoacid.[3] It is a major constituent of fuming sulfuric acid, oleum, and this is how most chemists encounter it. As confirmed by X-ray crystallography, the molecule consists of a pair of SO2(OH) groups joined by an oxide.[4]

  1. ^ International Union of Pure and Applied Chemistry (2005). Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005). Cambridge (UK): RSC–IUPAC. ISBN 0-85404-438-8. p. 130. Electronic version.
  2. ^ Perrin, D. D., ed. (1982) [1969]. Ionisation Constants of Inorganic Acids and Bases in Aqueous Solution. IUPAC Chemical Data (2nd ed.). Oxford: Pergamon (published 1984). Entry 62. ISBN 0-08-029214-3. LCCN 82-16524.
  3. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  4. ^ Hönle, Wolfgang (1991). "Crystal structure of H2S2O7 at 298 K". Zeitschrift für Kristallographie - Crystalline Materials. 196 (1–4). doi:10.1524/zkri.1991.196.14.279. S2CID 101311329.