Disulfur dioxide

From Infogalactic: the planetary knowledge core
Jump to: navigation, search
Disulfur dioxide
structure of disulfur dioxide, S2O2
space-filling model of the disulfur dioxide molecule
Names
Other names
disulfur(II)oxide
SO dimer
Identifiers
126885-21-0 [1]
Jmol 3D model Interactive image
  • InChI=1/O2S2/c1-3-4-2
    Key: AXYLJRYHRATPSG-UHFFFAOYNA-N
  • O=[S][S]=O
Properties
S2O2
Molar mass 96.1299 g/mol
Appearance gas
Structure
bent
Vapor pressure {{{value}}}
Related compounds
Related compounds
tetrasulfur
SO,
S3O
S2O
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Disulfur dioxide, dimeric sulfur monoxide or SO dimer is an oxide of sulfur.[2] The molecule is unstable with a lifetime of a few seconds.[3] It is an asymmetric top molecule.[1] The molecule adopts cis-planar structure with C2v symmetry with the two sulfur atoms joined.[4] The shape is the same as the tetrasulfur molecule S4.[4] The S-O bond length is 145.8 pm, shorter than in the sulfur monoxide monomer, and the S-S bond length is 202.45 pm. The OSS angle is 112.7°. S2O2 has a dipole moment of 3.17 D.[5]

Formation

Sulfur monoxide (SO) converts to disulfur dioxide (S2O2) spontaneously and reversibly.[5] So the substance can be generated by methods that produce sulfur monoxide. Disulfur dioxide has also been formed by an electric discharge in sulfur dioxide.[4] Another laboratory procedure is to react oxygen atoms with carbon oxysulfide or carbon disulfide vapour.[6]

Although elemental sulfur and sulfur dioxide do not combine, the exotic species atomic sulfur is extremely reactive and combines spontaneously with sulfur dioxide to form sulfur monoxide, the intermediate molecule formed is disulfur dioxide:[7]

S + SO2 S2O2
S2O2 ⇌ 2SO

Disulfur dioxide is also produced upon a microwave discharge in sulfur dioxide diluted in helium.[8] At a pressure of 0.1 mm Hg,five percent of the result is S2O2.[9]

Disulfur dioxide is formed transiently when hydrogen sulfide and oxygen undergo flash photolysis.[10]

At one time burning sulfur was thought to make the molecule based on the ultraviolet spectrum.[11]

Properties

The ionisation energy of disulfur dioxide is 9.93±0.02  eV.[6]

Reactions

Although disulfur dioxide exists in equilibrium with sulfur monoxide, it also reacts with sulfur monoxide to form sulfur dioxide and disulfur monoxide.[8][12]

Complexes

S2O2 can be a ligand with transition metals. It binds in the η2-S,S' position with both sulfur atoms linked to the metal atom.[13] This was first shown in 2003. The bis-(trimethylphosphine) thiirane S-oxide complex of platinum, when heated in toluene at 110 °C loses ethylene, and forms a complex with S2O2: (Ph3P)2PtS2O2.[14] Iridium atoms can also form a complex: cis-[(dppe)2IrS2]Cl with sodium periodate oxidises to [(dppe)2IrS2O] and then to [(dppe)2IrS2O2], with dppe being 1,2-Bis(diphenylphosphino)ethane.[15][16] This substance has the S2O2 in a cis position. The same conditions can make a trans complex, but this contains two separate SO radicals instead. The iridium complex can be decomposed with triphenyl phosphine to form triphenyl phosphine oxide, and triphenyl phosphine sulfide.[15]

A S2O2 macrocycle has nothing to do with this molecule, this is a larger organic ring molecule with sulfur and oxygen atoms positioned to be ligands for a metal ion, for example 5,8-dioxa-2,11-dithia-[12]-o-cyclophane.[17]

Anion

The S2O2 anion has been made in the gas phase, and may in fact have the trigonal shape with a sulfur atom attached to two oxygens and one other sulfur atom.[18]

Spectrum

Microwave

Transition Frequency MHz[4]
21,1−20,2 11013.840
41,3−40,4 14081.640
11,1−00,0 15717.946
40,4−31,3 16714.167
31,3−20,2 26342.817
42,2−41,3 26553.915
22,0−21,1 28493.046
60,6−51,5 30629.283
52,4−51,5 35295.199
51,5−40,4 35794.527

References

  1. 1.0 1.1 Lua error in package.lua at line 80: module 'strict' not found.
  2. Lua error in package.lua at line 80: module 'strict' not found.
  3. Lua error in package.lua at line 80: module 'strict' not found.
  4. 4.0 4.1 4.2 4.3 Lua error in package.lua at line 80: module 'strict' not found.
  5. 5.0 5.1 Spectroscopic studies of the SO2 discharge system. II. Microwave spectrum of the SO dimer Lovas F. J., Tiemann E., Johnson D.R. The Journal of Chemical Physics (1974), 60, 12, 5005-5010 doi:10.1063/1.1681015
  6. 6.0 6.1 Lua error in package.lua at line 80: module 'strict' not found.
  7. Lua error in package.lua at line 80: module 'strict' not found.
  8. 8.0 8.1 Lua error in package.lua at line 80: module 'strict' not found.
  9. Lua error in package.lua at line 80: module 'strict' not found.
  10. Lua error in package.lua at line 80: module 'strict' not found.
  11. Lua error in package.lua at line 80: module 'strict' not found.
  12. Lua error in package.lua at line 80: module 'strict' not found.
  13. Lua error in package.lua at line 80: module 'strict' not found.
  14. Lua error in package.lua at line 80: module 'strict' not found.
  15. 15.0 15.1 Lua error in package.lua at line 80: module 'strict' not found.
  16. Lua error in package.lua at line 80: module 'strict' not found.
  17. Lua error in package.lua at line 80: module 'strict' not found.
  18. Lua error in package.lua at line 80: module 'strict' not found.