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]
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| Names | |
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| Other names
disulfur(II)oxide
SO dimer | |
| Identifiers | |
3D model (JSmol)
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PubChem CID
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| Properties | |
| S2O2 | |
| Molar mass | 96.1299 g/mol |
| Appearance | gas |
| Structure | |
| bent | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
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toxic |
| Related compounds | |
Related compounds
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tetrasulfur SO, S3O S2O |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Structure
editDisulfur 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
editSulfur 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 isoelectronic to SO3, S=SO2, is believed to form during the thermal decomposition of cyclic vicinal alkyl thiosulfites.[12]
Properties
editThe 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
editAlthough 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
editS2O2 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
editThe S
2O−
2 radical anion has been observed in the gas phase. It may adopt a trigonal shape akin to SO3.[20]
Spectrum
editMicrowave
edit| Transition | Frequency (MHz)[5] |
|---|---|
| 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 |
In the Solar System
editThere 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
edit- ^ a b 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.
- ^ Holleman, Arnold F.; Wiber, Egon; Wiberg, Nils, eds. (2001). "Oxides of sulfur". Inorganic Chemistry. Academic Press. p. 530. ISBN 9780123526519.
- ^ Mitchell, Stephen C. (2004). Biological Interactions Of Sulfur Compounds. CRC Press. p. 7. ISBN 9780203362525.
- ^ a b 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.
- ^ a b c 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.
- ^ 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.
- ^ a b 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.
- ^ 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.
- ^ a b 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.
- ^ Sahoo, Balaram; Nayak, Nimai Charan; Samantaray, Asutosh; Pujapanda, Prafulla Kumar (2012). Inorganic Chemistry. PHI Learning. p. 461. ISBN 9788120343085. Retrieved 2013-05-16.
- ^ 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.
- ^ Harpp, David N. (1997). "The sulfur diatomics". Phosphorus, Sulfur, and Silicon. 120. Amsterdam, NL: Gordon & Breach: 49. doi:10.1080/10426509708545509.
- ^ a b 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.
- ^ "Rare molecule on Venus may help explain planet's weather". CBC News. Retrieved 2016-11-11.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ a b 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.
- ^ 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.
- ^ Clements, Todd G.; Hans-Jürgen Deyerl; Robert E. Continetti (2002). "Dissociative Photodetachment Dynamics of S
2O−
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.