Sulfur oxoacid

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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 oxoacids; 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 peroxo groups
  • terminal S=S
  • chains of (-S-)n
Acid Formula Oxidation state(s) Structure Related anions Notes
Sulfuric acid H2SO4 VI sulfuric Sulfate, SO2−
4
and hydrogen sulfate commonly known as bisulfate, HSO
4
Best known and industrially significant.
Polysulfuric acids including disulfuric acid or pyrosulfuric acid H2SO4·nSO3 VI disulfuric Disulfate (commonly known as pyrosulfate), S
2
O2−
7
and trisulfate, S
3
O2−
10
Pure disulfuric acid melts at 36 °C.

Present in fuming sulfuric acid, oleum. Examples known for n=1,2.

Peroxymonosulfuric acid H2SO5 VI peroxymonosulfuric Peroxymonosulfate, OOSO2−
3
"Caro's acid", a solid melting at 45 °C
Peroxydisulfuric acid H2S2O8 VI peroxydisulfuric Peroxydisulfate, O
3
SOOSO2−
3
"Marshall's acid", a solid melting at 65 °C.
Dithionic acid H2S2O6 V dithionic Dithionate, O
3
SSO2−
3
Not isolated in pure form, only concentrated solutions have been prepared
Thiosulfuric acid H2S2O3 -II (for the terminal sulfur) , VI (for the central atom) thiosulfuric Thiosulfate, S
2
O2−
3

Hydrogenthiosulfate HS
2
O
3
(ammonium salt prepared in anhydrous methanol at −80 °C[1])
Aqueous solutions decompose.
Disulfurous acid or pyrosulfurous acid H2S2O5 V (of the sulfur atom bonded to 3 oxygen atoms), III (of other sulfur atom) disulfurous Disulfite commonly known as metabisulfite, S
2
O2−
5
Not known.
Sulfurous acid H2SO3 IV sulfurous Bisulfite, HSO
3
and sulfite, SO2−
3
Not known.
Dithionous acid H2S2O4 III dithionous Dithionite, O
2
SSO2−
2
Not known.
Sulfoxylic acid H2SO2 II sulfoxylic Sulfoxylate, SO2−
2
Free acid not known
Polythionic acid H2SxO6 0 (for the bridging S atoms), V (for the terminal central S atoms) polythionic Polythionates, O
3
S(S
x−2
)SO2−
3
. Example trithionate, tetrathionate, pentathionate, hexathionate, heptathionate, octathionate, nonathionate, decathionate, undecathionate, dodecathionate, tridecathionate and tetradecathionate.
Examples known with x= 3, 4, 5, 6, 7, 8, 10, 12, 14.
Thiosulfurous acid H2S2O2 -I (for the exterior sulfur atom ) , III (for the central atom) Thioschweflige Säure.svg Thiosulfites Not known
Dihydroxydisulfane H2S2O2 I hypodithionous Acid known

See also[edit]

References[edit]

  1. ^ Raman spectroscopic discovery of the hydrogenthiosulphate anion, HSSO
    3
    , in solid NH4HS2O3 Steudel Rr.; Prenzel A Zeitschrift für Naturforschung 1989,44, 12, 1499-1502

External links[edit]