Disulfur dioxide

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Disulfur dioxide
structure of disulfur dioxide, S2O2 Disulfur-dioxide-2D-dimensions.png
structure of disulfur dioxide, S2O2
space-filling model of the disulfur dioxide molecule Disulfur-dioxide-3D-vdW-A.png
space-filling model of the disulfur dioxide molecule
Names
Other names
disulfur(II)oxide
SO dimer
Identifiers
3D model (JSmol)
PubChem CID
  • InChI=1/O2S2/c1-3-4-2
    Key: AXYLJRYHRATPSG-UHFFFAOYNA-N
  • O=[S][S]=O
Properties
S2O2
Molar mass 96.1299 g/mol
Appearancegas
Structure
bent
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
toxic
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).

Disulfur dioxide, dimeric sulfur monoxide or SO dimer is an oxide of sulfur with the formula S2O2. [2] The solid is unstable with a lifetime of a few seconds at room temperature. [3]

Contents

Structure

Disulfur dioxide adopts a cis planar structure with C2v symmetry. The S−O bond length is 145.8 pm, shorter than in sulfur monoxide. The S−S bond length is 202.45 pm and the O−S−S angle is 112.7°. S2O2 has a dipole moment of 3.17 D. [4] It is an asymmetric top molecule. [1] [5]

The electronic ground state is a singlet, unlike disulfur or dioxygen. [6]

Formation

Sulfur monoxide (SO) converts to disulfur dioxide (S2O2) spontaneously and reversibly. [4] 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. [5] Another laboratory procedure is to react oxygen atoms with carbonyl sulfide or carbon disulfide vapour. [7]

Although most forms of elemental sulfur (S8 and other rings and chains) do not combine with SO2, atomic sulfur does so to form sulfur monoxide, which dimerizes: [8]

S + SO2 → S2O2 ⇌ 2 SO

Disulfur dioxide is also produced upon a microwave discharge in sulfur dioxide diluted in helium. [9] At a pressure of 0.1 mmHg (13 Pa), five percent of the result is S2O2. [10]

Disulfur dioxide is formed transiently when hydrogen sulfide and oxygen undergo flash photolysis. [11]

A branched isomer valence isoelectronic to SO3, S=SO2, is believed to form during the thermal decomposition of cyclic vicinal alkyl thiosulfites. [12]

Properties

The ionization energy of disulfur dioxide is 9.93±0.02 eV. [7]

Disulfur dioxide absorbs at 320–400 nm, as observed of the Venusian atmosphere, [13] and is believed to have contributed to the greenhouse effect on that planet. [14]

Reactions and decomposition

Although disulfur dioxide exists in equilibrium with sulfur monoxide, it also reacts with sulfur monoxide to form sulfur dioxide and disulfur monoxide. [9] [15]

Decomposition of S2O2 proceeds via the following disproportionation reaction:

S2O2 → SO2 + 1/8 S8

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. [16] 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)2Pt(S2O2). [17] Iridium atoms can also form a complex: cis-[(dppe)2IrS2]Cl with sodium periodate oxidizes to [(dppe)2IrS2O] and then to [(dppe)2IrS2O2], with dppe being 1,2-bis(diphenylphosphino)ethane. [18] [19] 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 triphenylphosphine to form triphenylphosphine oxide and triphenylphosphine sulfide. [18]

Anion

The S
2O−
2 radical anion has been observed in the gas phase. It may adopt a trigonal shape akin to SO3. [20]

Spectrum

Microwave

TransitionFrequency (MHz) [5]
21,1−20,211013.840
41,3−40,414081.640
11,1−00,015717.946
40,4−31,316714.167
31,3−20,226342.817
42,2−41,326553.915
22,0−21,128493.046
60,6−51,530629.283
52,4−51,535295.199
51,5−40,435794.527

In the Solar System

There is some evidence that disulfur dioxide may be a small component in the atmosphere of Venus, and that it may substantially contribute of the planet's severe greenhouse effect. [13] It is not found in any substantive quantity in Earth's atmosphere.

References

  1. 1 2 Demaison, Jean; Vogt, Jürgen (2011). "836. O2S2 Disulfur dioxide" (PDF). Asymmetric Top Molecules, Part 3. Landolt–Börnstein: Group II Molecules and Radicals. Vol. 29D3. Springer. p. 492. doi:10.1007/978-3-642-14145-4_258. ISBN   9783642141454.
  2. ↑ Holleman, Arnold F.; Wiber, Egon; Wiberg, Nils, eds. (2001). "Oxides of sulfur". Inorganic Chemistry. Academic Press. p. 530. ISBN   9780123526519.
  3. ↑ Mitchell, Stephen C. (2004). Biological Interactions Of Sulfur Compounds. CRC Press. p. 7. ISBN   9780203362525.
  4. 1 2 Lovas, F. J. (1974). "Spectroscopic studies of the SO2 discharge system. II. Microwave spectrum of the SO dimer". The Journal of Chemical Physics. 60 (12): 5005. Bibcode:1974JChPh..60.5005L. doi:10.1063/1.1681015.
  5. 1 2 3 Thorwirth, Sven; Theulé, P.; Gottlieb, C. A.; Müller, H. S. P.; McCarthy, M. C.; Thaddeus, P. (2006). "Rotational spectroscopy of S2O: vibrational satellites, 33S isotopomers, and the submillimeter-wave spectrum" (PDF). Journal of Molecular Structure. 795 (1–3): 219–229. Bibcode:2006JMoSt.795..219T. doi:10.1016/j.molstruc.2006.02.055.
  6. ↑ Steudel, Ralf (2003). "Sulfur-rich oxides SnO and SnO2". In Steudel, Ralf (ed.). Topic in Current Chemistry. Topics in Current Chemistry. Vol. 231. Berlin: Springer. p. 211. doi:10.1007/b11909. ISBN   3-540-40378-7. ISSN   0340-1022. LCCN   74-644622.
  7. 1 2 Cheng, Bing-Ming; Hung, Wen-Ching (1999). "Photoionization efficiency spectrum and ionization energy of S2O2". The Journal of Chemical Physics. 110 (1): 188. Bibcode:1999JChPh.110..188C. doi:10.1063/1.478094. ISSN   0021-9606.
  8. ↑ Murakami, Yoshinori; Onishi, Shouichi; Kobayashi, Takaomi; Fujii, Nobuyuki; Isshiki, Nobuyasu; Tsuchiya, Kentaro; Tezaki, Atsumu; Matsui, Hiroyuki (2003). "High Temperature Reaction of S + SO2 → SO + SO: Implication of S2O2 Intermediate Complex Formation". The Journal of Physical Chemistry A. 107 (50): 10996–11000. Bibcode:2003JPCA..10710996M. doi:10.1021/jp030471i. ISSN   1089-5639.
  9. 1 2 Field, T. A.; Slattery, A. E.; Adams, D. J.; Morrison, D. D. (2005). "Experimental observation of dissociative electron attachment to S2O and S2O2 with a new spectrometer for unstable molecules" (PDF). Journal of Physics B: Atomic, Molecular and Optical Physics. 38 (3): 255–264. Bibcode:2005JPhB...38..255F. doi:10.1088/0953-4075/38/3/009. ISSN   0953-4075. S2CID   122789729. Archived from the original (PDF) on 2015-09-24. Retrieved 2013-05-13.
  10. ↑ Sahoo, Balaram; Nayak, Nimai Charan; Samantaray, Asutosh; Pujapanda, Prafulla Kumar (2012). Inorganic Chemistry. PHI Learning. p. 461. ISBN   9788120343085 . Retrieved 2013-05-16.
  11. ↑ Compton, R. G.; Bamford, C. H.; Tipper, C. F. H. (1972). "Oxidation of H2S". Reactions of Non-Metallic Inorganic Compounds. Comprehensive Chemical Kinetics. Elsevier. p. 50. ISBN   9780080868011.
  12. ↑ Harpp, David N. (1997). "The sulfur diatomics". Phosphorus, Sulfur, and Silicon. 120. Amsterdam, NL: Gordon & Breach: 49. doi:10.1080/10426509708545509.
  13. 1 2 Frandsen, B. N.; Wennberg, P. O.; Kjærgaard, H. G. (2016). "Identification of OSSO as a near-UV absorber in the Venusian atmosphere" (PDF). Geophysical Research Letters. 43 (21): 11146–11155. Bibcode:2016GeoRL..4311146F. doi: 10.1002/2016GL070916 .
  14. ↑ "Rare molecule on Venus may help explain planet's weather". CBC News. Retrieved 2016-11-11.
  15. ↑ Herron, J. T.; Huie, R. E. (1980). "Rate constants at 298 K for the reactions SO + SO + M → (SO)2 + M and SO + (SO)2 → SO2 + S2O". Chemical Physics Letters. 76 (2): 322–324. Bibcode:1980CPL....76..322H. doi:10.1016/0009-2614(80)87032-1.
  16. ↑ Halcrow, Malcolm A.; Huffman, John C.; Christou, George (1994). "Synthesis, Characterization, and Molecular Structure of the New S2O Complex Mo(S2O)(S2CNEt2)3·1/2Et2O" (PDF). Inorganic Chemistry. 33 (17): 3639–3644. doi:10.1021/ic00095a005. ISSN   0020-1669. Archived from the original (PDF) on 2015-11-06. Retrieved 2013-05-13.
  17. ↑ Lorenz, Ingo-Peter; Kull, Jürgen (1986). "Complex Stabilization of Disulfur Dioxide in the Fragmentation of Thiirane S-Oxide on Bis(triphenylphosphane)platinum(0)". Angewandte Chemie International Edition in English. 25 (3): 261–262. doi:10.1002/anie.198602611. ISSN   0570-0833.
  18. 1 2 Schmid, Günter; Ritter, Günter; Debaerdemaeker, Tony (1975). "Die Komplexchemie niederer Schwefeloxide. II. Schwefelmonoxid und Dischwefeldioxid als Komplexliganden" [The complex chemistry of lower sulfur oxides. II. Sulfur monoxide and disulfur dioxide as complex ligands]. Chemische Berichte. 108 (9): 3008–3013. doi:10.1002/cber.19751080921. ISSN   0009-2940.
  19. ↑ Nagata, K.; Takeda, N.; Tokitoh, N. (2003). "Unusual Oxidation of Dichalcogenido Complexes of Platinum". Chemistry Letters. 32 (2): 170–171. doi:10.1246/cl.2003.170. ISSN   0366-7022.
  20. ↑ Clements, Todd G.; Hans-Jürgen Deyerl; Robert E. Continetti (2002). "Dissociative Photodetachment Dynamics of S
    2    O−
    2    "     (PDF). The Journal of Physical Chemistry A. 106 (2): 279–284. Bibcode:2002JPCA..106..279C. doi:10.1021/jp013329v. ISSN   1089-5639 . Retrieved 2013-05-13.
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