Sulfur oxoacid
Appearance
The sulfur oxoacids are chemical compounds that contain sulfur, oxygen and hydrogen. The best known and most important industrially is sulfuric acid. Sulfur has a number of oxo acids; however, some of these are known only from their salts (these are shown in italics in the table below). The acids that have been characterised contain a variety of structural features, for example:
- tetrahedral sulfur when coordinated to oxygen
- terminal and bridging oxygen atoms
- terminal and bridging peroxo groups
- terminal S=S
- chains of (-S-)n
Acid | Formula | S oxdtn state | Structure | Related anions | Notes |
Sulfuric acid | H2SO4 | VI | ![]() |
Sulfate, SO42− and hydrogen sulfate commonly known as bisulfate | Best known and industrially significant |
Disulfuric acid or pyrosulfuric acid | H2S2O7 | VI | ![]() |
Disulfate commonly known as pyrosulfate, S2O72− | Pure form melts at 36°C. Present in fuming sulfuric acid, oleum |
Peroxymonosulfuric acid | H2SO5 | VI | peroxymonosulfuric | Peroxymonosulfate, OOSO32− | "Caro's acid", a solid melting at 45°C |
Peroxydisulfuric acid | H2S2O8 | VI | ![]() |
Peroxydisulfate, O3SOOSO32− | A solid melting at 65°C. |
Dithionic acid | H2S2O6 | V | dithionic | Dithionate, O3SSO32− | Not obtained pure, only concentrated solutions |
Thiosulfuric acid | H2S2O3 | IV | ![]() |
Thiosulfate, S2O32− Hydrogenthiosulfate HS2O3− (ammonium salt prepared in anhydrous methanol at -80 °C [1]) |
Aqueous solutions decompose. |
Disulfurous acid | H2S2O5 | IV | ![]() |
Disulfite commonly known as metabisulfite, S2O52− | Not known |
Sulfurous acid | H2SO3 | IV | sulfurous | Bisulfite, HSO3− and sulfite, SO32− | Not known. |
Dithionous acid | H2S2O4 | III | ![]() |
Dithionite, O2SSO22− | Not known. |
Polythionic acid | H2SxO6 | ![]() |
Polythionate, O3S(Sx-2)SO32−. Example tetrathionate. | Examples known with x= 3, 4, 5, 6, 7, 8, 10, 12, 14. |
External links
- Sulfur+Acids at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Sulfur oxoacids along with other acids containing sulfur
Footnotes
- ^ Raman spectroscopic discovery of the hydrogenthiosulphate anion, HSSO3−, in solid NH4HS2O3 Steudel Rr.; Prenzel A Zeitschrift für Naturforschung 1989,44, 12, 1499-1502
Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.