View source for Sulfanyl

{{For|the chemistry of organo thiyl radicals|Thiyl radical}}
{{Chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 470473350
| ImageFile = HS-CM-3D-balls.png
| ImageFile_Ref = {{chemboximage|correct|??}}
| ImageSize = 100
| ImageName = Ball and stick model of sulfanyl
| ImageCaption = {{legend|yellow|Sulfur, S}}{{legend|white|Hydrogen, H}}
| SystematicName = Sulfanyl<ref name = "sulfanyl (CHEBI:29312)">{{cite web|title = sulfanyl (CHEBI:29312)|url = http://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:29312|work = Chemical entities of biological interest|publisher = European Bioinformatics Institute|access-date = 8 October 2011|location = UK|date = 6 November 2006|at = Main}}</ref> ''(substitutive)''<br />
Hydridosulfur(•)<ref name = "sulfanyl (CHEBI:29312)" /> ''(additive)''
| OtherNames = λ<sup>1</sup>-Sulfane<ref>{{cite web|title = Mercapto radical – Compound summary|url = https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5460613&loc=ec_rcs|work = PubChem Compound|publisher = National Center for Biotechnology Information|access-date = 12 October 2011|location = USA|date = 16 September 2004|at = Identification and related records}}</ref>
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|changed|??}}
| CASNo = 13940-21-1
| PubChem = 5460613
| ChemSpiderID = 4574111
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChEBI = 29312
| ChEBI_Ref = {{ebicite|correct|EBI}}
| Gmelin = 299
| SMILES = [SH]
| StdInChI = 1S/HS/h1H
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = PXQLVRUNWNTZOS-UHFFFAOYSA-N
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
}}
|Section2={{Chembox Properties
| Formula = {{Chem|HS}}<sup>•</sup>
| MolarMass = 33.073 g mol<sup>−1</sup>
| Appearance = Yellow gas<ref name="Zahnle">{{Cite journal|title=Atmospheric sulfur photochemistry on hot Jupiters|journal = The Astrophysical Journal|volume = 701|issue = 1|pages = L20–L24|last=Zahnle|first=Kevin |author2=Mark S. Marley |author3=R. S. Freedman |author4=K. Lodders |author4-link=Katharina Lodders|author5=J. J. Fortney |date=26 June 2009|arxiv = 0903.1663v2|doi = 10.1088/0004-637X/701/1/L20|bibcode = 2009ApJ...701L..20Z|s2cid = 16431314}}</ref>
| Solubility = Reacts
}}
|Section3={{Chembox Thermochemistry
| DeltaHf = 139.33 kJ mol<sup>−1</sup>
| Entropy = 195.63 J K<sup>−1</sup> mol<sup>−1</sup>
}}
|Section4={{Chembox Related
| OtherFunction_label = radicals
| OtherFunction = [[Hydroxyl]]
| OtherCompounds = [[Hydrogen sulfide]]<br />
[[Hydrogen disulfide]]
}}
}}

'''Sulfanyl''' ('''{{Chem|HS}}<sup>•</sup>'''), also known as the '''mercapto radical''', '''hydrosulfide radical''', or '''hydridosulfur''', is a simple [[Radical (chemistry)|radical]] molecule consisting of one hydrogen and one sulfur atom. The S-H distance in the radical is 0.134&nbsp;nm.<ref name="Ellingson">{{cite journal|url=http://static.msi.umn.edu/rreports/2007/267.pdf|title=Explanation of the unusual temperature dependence of the atmospheric important <sup>•</sup>OH + H<sub>2</sub>S → H<sub>2</sub>O + <sup>•</sup>SH reaction and prediction of the rate constant at combustion temperatures|last=Ellingson|first=Benjamin A.|author2=Donald G. Truhlar |date=1 August 2007|access-date=20 October 2011|doi=10.1021/ja072538b|pmid=17910447|journal=J. Am. Chem. Soc.|volume=129 |issue=42|pages=12765–12771 [12769] |format=reprint}}</ref>  The radical is also proposed to be formed by the action of [[ultraviolet radiation]] on hydrogen sulfide.  A [[wavelength]] of 190&nbsp;nm gives maximum absorption.<ref>{{cite book|last1=Hollaender|first1=Alexander|last2=Livingston|first2=Robert|title=Radiation Biology|chapter-url=https://archive.org/stream/radiationbiology02holl/radiationbiology02holl_djvu.txt|year=1955|publisher=McGraw Hill|page=27|chapter=1}}</ref>


==Gaseous sulfanyl==
Sulfanyl is one of the top three sulfur-containing gasses in [[gas giant]]s such as [[Jupiter]] and is very likely to be found in [[brown dwarf]]s and cool stars. It was originally discovered by Margaret N. Lewis and John U. White at the [[University of California]] in 1939.<ref name="Lewis">{{cite journal|last=Lewis|first=Margaret|author2=John U. White |year=1939|title=The band spectrum of HS|journal=Physical Review|volume=55|issue=10|pages=894–898|doi=10.1103/PhysRev.55.894|bibcode = 1939PhRv...55..894L }}</ref> They observed molecular absorption bands around 325&nbsp;nm belonging to the system designated by <big><sup>2</sup>Σ<sup>+</sup> ← <sup>2</sup>Π<sub>i</sub></big>.  They generated the radical by means of a radio frequency discharge in [[hydrogen sulfide]].<ref>{{cite journal|last=Harrison|first=Jeremy J.|author2=Bryce E. Williamson |date=November 2005|title=Magnetic circular dichroism of the mercapto radical in noble-gas matrices|journal=Journal of the Indian Institute of Science|volume=85|pages=391–402|url=http://journal.library.iisc.ernet.in/vol200506/paper6/391-402.pdf}}</ref> HS<sup>•</sup> is formed during the degradation of hydrogen sulfide in the atmosphere of the Earth.  This may be a deliberate action to destroy odours or a natural phenomenon.<ref>{{cite web|url=http://www.ispc-conference.org/ispcproc/papers/275.pdf|title=Environmental odour control by atmospheric dielectric barrier discharge|last=Mercado-Cabrera|first=Antonio |author2=B. Jaramillo-Sierra |author3=S.R. Barocio |author4=R. Valencia-Alvarado |author5=M. Pacheco-Pacheco |author6=R. Peña-Eguiluz |author7=R. Lopez-Callejas |author8=A. Muñoz-Castro |author9=A. De la Piedad-Beneitez |date=29 April 2009|publisher=ISPC|access-date=20 October 2011}}</ref>

Absorption lines of sulfanyl in space were first detected in the [[infrared]] by Yamamura (2000) in a star [[R And]]. In the sun <sup>•</sup>SH was detected at several [[ultraviolet]] [[wavelength]]s: 326.0459, 327.5468, 328.9749, 330.0892 and 330.1112&nbsp;nm.<ref>{{cite journal|volume=387|doi=10.1051/0004-6361:20020364|bibcode=2002A&A...387L...6B|date=May 2002|journal=Astronomy and Astrophysics|title=Detection of the mercapto radical SH in the solar atmosphere|author1=Sveta V. Berdyugina  |author2=W.C. Livingston |pages=L6–L9 |doi-access=free}}</ref>

Sulfanyl has been detected in [[interstellar gas]],<ref>{{cite web|url=https://www.npr.org/2011/10/01/140877924/flying-telescope-makes-an-out-of-this-world-find|title=Flying telescope makes an out-of-this-world find|last=Palca|first=Joe|date=1 October 2011|publisher=NPR|access-date=8 October 2011}}</ref> and it is possibly present in comets.<ref>{{cite web|title= The cosmic ice laboratory – Cometary molecules|url=http://science.gsfc.nasa.gov/691/cosmicice/cometary.html}}</ref>

Various theoretical studies have examined HS<sup>•</sup> in atmospheres. In Earth's atmosphere
HS<sup>•</sup> reacts with NO<sub>2</sub> to make two products HSNO<sub>2</sub> and HSONO.  HSONO decomposes to HSO and NO.
HS<sup>•</sup> also reacts with O<sub>2</sub> and N<sub>2</sub>O.<ref name="resende">{{cite journal|last=Resende|first=Stella M.|year=2007|title=The atmospheric oxidation of the HS radical: Reaction with NO<sub>2</sub>|journal=Journal of Atmospheric Chemistry|volume=56|issue=1|pages=21–32|doi=10.1007/s10874-006-9040-z|bibcode=2006JAtC...56...21R|s2cid=95081477}}</ref> HS<sup>•</sup> can also react with Cl<sub>2</sub> producing HSCl and a Cl<sup>•</sup> atom.<ref>{{cite journal|last=Resende|first=Stella M.|author2=Fernando R Ornellas |date=25 February 2000|title=Atmospheric reaction between the HS radical and chlorine|journal=Chemical Physics Letters|volume=318|issue=4–5|pages=340–344|doi=10.1016/S0009-2614(00)00019-1|bibcode=2000CPL...318..340R}}</ref> HS<sup>•</sup> destroys [[ozone]] producing HSO<sup>•</sup> and oxygen.<ref name="yosh">{{cite journal|last=Yoshimura|first=Yasunori|author2=Toshio Kasai, Hiroshi Ohoyama and Keiji Kuwata|year=1995|title=Nascent HF + and HSO(2A') formations in the elementary reactions of F + H<sub>2</sub>S and HS + O<sub>3</sub> and the internal energy distributions|journal=Canadian Journal of Chemistry|volume=73|issue=2|pages=204–221|doi=10.1139/v95-029|last3=Ohoyama|first3=Hiroshi|last4=Kuwata|first4=Keiji|doi-access=free}}</ref>  HS<sup>•</sup> is formed in the Earth's atmosphere by the reaction of HO<sup>•</sup>, the [[hydroxyl radical]], on [[carbon disulfide]], [[carbon oxysulfide]] and [[hydrogen sulfide]] with side products of [[carbon dioxide]] and water.  Photodissociation of hydrogen sulfide also produces the radical in air.<ref name="Furones">{{cite web|url=https://estudogeral.sib.uc.pt/jspui/bitstream/10316/7489/3/thesis-MYBF.pdf|title=A theoretical study on the HSO<sub>2</sub> molecular system|last=Furones|first=Maikel Yusat Ballester|year=2008|publisher=Universidade de Coimbra|pages=1, 37|access-date=20 October 2011|location=Coimbra}}</ref>

In a planetary atmosphere that contains H<sub>2</sub>S, HS<sup>•</sup> will be formed if the temperature and pressure are high enough.
The ratio of H<sub>2</sub>S and HS<sup>•</sup> is given by:

:log(''X''{{sub|H<sub>2</sub>S}}/''X''{{sub|HS}}) = &minus;3.37 + 8785/''T'' + 0.5 log ''P<sub>T</sub>'' + 0.5 log ''X''<sub>H<sub>2</sub></sub>

For a hydrogen dominated atmosphere in a gas giant or star: H<sub>2</sub>S has the same level as HS<sup>•</sup> at 
:<math alt="log ''P{{sub|T}}'' = 6.82 &minus; 17570/''T''">\log P_T = 6.82 - 17570/T</math>.
At higher temperatures HS<sup>•</sup> breaks up into sulfur vapour and H<sub>2</sub>.  The line of equal S and HS concentration follows the line
:<math alt="log ''P{{sub|T}}'' = 4.80 &minus; 14522/''T''>\log P_T = 4.80 - 14522/T</math>.  
The lines of equal concentration cross at 1509&nbsp;K and 1.51&nbsp;Pa, with HS<sup>•</sup> being left out of the mix at lower temperatures and pressures. <sup>•</sup>SH is expected to be the second or third most common sulfur containing gas in [[gas giant]]s or [[brown dwarf]]s.<ref>{{cite journal|last1=Visscher|first1=Channon|first2=Katharina |last2=Lodders |author2-link=Katharina Lodders|first3= Bruce Jr.|last3=Fegley|date=10 September 2006|title=Atmospheric chemistry in giant planets, brown dwarfs, and low-mass dwarf stars. II. Sulfur and phosphorus|journal=The Astrophysical Journal|volume=648|pages=1181–1195|issue=2|arxiv=astro-ph/0511136|doi=10.1086/506245|bibcode = 2006ApJ...648.1181V |s2cid=17874854}}</ref>

==Organic thiyl==
The [[Organic compound|organic]] analogue of sulfanyl is [[thiyl radical]] with the formula {{chem2|RS^{•}|}}, where R is some organic group (e.g., [[alkyl]] or [[aryl]]). Thermal decomposition of mercaptans, such as [[ethyl mercaptan]] has been proposed to involve {{Chem|HS}}<sup>•</sup>.<ref>{{cite journal|last=Sehon|first=A. H.|author2=B. deB. Darwent |date=October 1954|title=The thermal decomposition of mercaptans|journal=Journal of the American Chemical Society|volume=76|issue=19|pages=4806|doi=10.1021/ja01648a011}}</ref>

==HS. in biology==
In humans [[SOD1|superoxide dismutase [Cu-Zn]]] is proposed to convert the hydrosulfide ion (HS<sup>−</sup>) to {{Chem|HS}}<sup>•</sup>.  In the proposed mechanism Cu<sup>2+</sup> is convert to Cu<sup>+</sup>.<ref name="lyons">{{cite book|url=http://www.ffame.org/tlyons/mibs36.125-177.pdf|title=Biological chemistry of copper-zinc superoxide dismutase and its link to amyotrophic lateral sclerosis|last=Lyons|first=Thomas J.|author2=Edith Butler Gralla |author3=Joan Selverstone Valentine |year=1999|journal=Metal Ions in Biological Systems|volume=36|publisher=Marcel Decker Inc|page=139|access-date=10 October 2011|location=Basel, Switzerland|pmid=10093924|isbn=978-0-8247-1956-2}}</ref>

[[Sulfide dehydrogenase]] as found in [[Sulfur-reducing bacteria|sulfur bacteria]] catalyses the oxidation of HS<sup>−</sup>.  It has been proposed that this reaction proceeds via {{Chem|HS}}<sup>•</sup>, by removing a single electron.<ref>{{cite journal|last=Sorokina|first=Dimitry Yu|author2=Govardus A.H de Jong |author3=Lesley A. Robertson |author4=Gijs J. Kuenen |date=1 May 1998|title=Purification and characterization of sulfide dehydrogenase from alkaliphilic chemolithoautotrophic sulfur-oxidizing bacteria|journal=FEBS Letters|volume=427|issue=1|pages=11–14|pmid=9613590|doi=10.1016/S0014-5793(98)00379-2|s2cid=2818096|doi-access=free}}</ref>

When some sulfur minerals are leached with ferric ions, HS<sup>•</sup> is proposed to proceed as follows:
:MS + Fe<sup>3+</sup> + 2H<sup>+</sup> → M<sup>2+</sup> + Fe<sup>2+</sup> + H<sub>2</sub>S<sup>•+</sup>

with the H<sub>2</sub>S<sup>•+</sup> radical then passing a proton to water to make the HS<sup>•</sup> radical. M is a metal such as zinc or copper.<ref name="schippers">{{cite journal|last=Schippers|first=Axel|author2=Wolfgang Sand |date=January 1999 |title=Bacterial leaching of metal sulfides proceeds by two indirect mechanisms via thiosulfate or via polysulfides and sulfur|journal=Applied and Environmental Microbiology|volume=65|issue=1|pages=319–321|doi=10.1128/AEM.65.1.319-321.1999|url= |pmid=9872800|pmc=91023|bibcode=1999ApEnM..65..319S}}</ref>  This has potential for [[bioleaching]] in metallic ore extraction.

The [[hydrosulfide ion]] HS<sup>−</sup> can be oxidized with [[cerium (IV) sulfate]].  The process again has been proposed to involve HS<sup>•</sup>.<ref name=pos>{{cite journal|last=Pos|first=Willer H.|author2=Daniel D. Riemer |author3=Rod G. Zika |year=1998|title=Carbonyl sulfide (OCS) and carbon monoxide (CO) in natural waters: evidence of a coupled production pathway|journal=Marine Chemistry|volume=62|issue=1–2|pages=89–101|doi=10.1016/S0304-4203(98)00025-5|doi-access=free|bibcode=1998MarCh..62...89P }}</ref>

==Reactions==
In water HS is proposed to react with O<sub>2</sub> producing SO<sub>2</sub><sup>−</sup> and H<sup>+</sup>. This SO<sub>2</sub><sup>−</sup> is further proposed to react with O<sub>2</sub> to give SO<sub>2</sub> and [[superoxide]] O<sub>2</sub><sup>−</sup>. 

HS<sup>•</sup> has an equilibrium with S<sup>− •</sup> and H<sup>+</sup>. 

The hydroxyl radical <sup>•</sup>OH has also been proposed to combine with H<sub>2</sub>S to form HS<sup>•</sup> and water.<ref name="Dong">{{cite journal|last=Fang|first=Hao Jie|author2=Dong Wen Bo |author3=Zhang Ren Xi |author4=Hou, Hui Qi|date=June 2006|title=水相中·HS 的光谱表征及其与氧气的反应研究 |trans-title= Spectrum of<sup>•</sup>HS and its reactions with oxygen in aqueous solution|journal=Acta Physico-Chimica Sinica|volume=22|issue=6|pages=761–763|url=http://www.whxb.pku.edu.cn/EN/abstract/abstract22924.shtml|access-date=12 October 2011|language=zh|doi=10.3866/PKU.WHXB20060623 |url-access=subscription}}</ref>  Other reactions investigated are:<ref>{{cite journal|url=http://kinetics.nist.gov/kinetics/Detail?id=1981TIE/WAM80:0|title=Spectroscopy and reaction kinetics of HS radicals|volume=82|issue=1|pages=80–84|last=Tiee|first=J.J.|journal=Kinetics Database|publisher=NIST|access-date=13 October 2011|bibcode=1981CPL....82...80T|year=1981|doi=10.1016/0009-2614(81)85111-1|url-access=subscription}}</ref><ref name="schippers"/>
:HS<sup>•</sup> + ethylene
:HS<sup>•</sup> + O<sub>2</sub> → HO<sup>•</sup> + [[sulfur monoxide|SO]]
:2 HS<sup>•</sup>  → H<sub>2</sub>S<sub>2</sub>
:2 HS<sup>•</sup>  →  H<sub>2</sub> and S
:H<sub>2</sub>S<sub>2</sub> + HS<sup>•</sup> -> HS–S<sup>•</sup> + H<sub>2</sub>S
The [[hydrogen disulfide]] is well known.

==Properties==
The ionization energy of HS is 10.4219&nbsp;eV.<ref>{{cite journal|last1=Cheng|first1=B. M.|last2=Chew |first2=E. P. |last3=Hung|first3=Wen-Ching|last4=Eberhard|first4=Jürg|author-link5=Yuan-Pern Lee|last5=Lee|first5=Yuan-Pern |date=May 1998|title=Photoionization studies of sulfur radicals and products of their reactions|journal=Journal of Synchrotron Radiation|volume=5|issue=3|pages=1041–3|doi=10.1107/S0909049597016075|pmid=15263738|bibcode=1998JSynR...5.1041C |url=http://journals.iucr.org/s/issues/1998/03/00/mz3378/mz3378.pdf}}</ref> The reduction potential to go to HS<sup>−</sup> is 0.92&nbsp;eV.<ref name="das">{{cite journal|last=Das|first=T. N.|author2=R. E. Huie |author3=P. Neta |author4=S. Padmaja |date=11 June 1999|title=Reduction potential of the sulfhydryl radical: pulse radiolysis and laser flash photolysis studies of the formation and reactions of <sup>•</sup>SH and HS–SH<sup>•−</sup> in aqueous solutions|journal=The Journal of Physical Chemistry A|volume=103|issue=27|pages=5221–5226|doi=10.1021/jp9907544|bibcode=1999JPCA..103.5221D}}</ref> HS<sup>•</sup> in water can ionize to S<sup>•−</sup> and H<sup>+</sup>. The S<sup>•−</sup> can catalyze a [[cis-trans]] conversion in [[lipid]]s.<ref>{{cite journal|last=Lykakis|first=Ioannis N.|author2=Carla Ferreri |author3=Chryssostomos Chatgilialoglu |date=19 January 2007|title=The sulfhydryl radical (HS<sup>•</sup>/S<sup>•−</sup>): A contender for the isomerization of double bonds in membrane lipids|journal=Angewandte Chemie|volume=46|issue=11|pages=1914–1916|doi=10.1002/anie.200604525|pmid=17450618}}</ref>

HS<sup>•</sup> reacts with [[carboxylic acids]] to make [[carbonyl sulfide]] (COS) and probably is the main source of this substance in the atmosphere of Earth.<ref name=pos/>

==Related molecules==
HS—S<sup>•</sup> is called disufanyl with lengthening chains as trisulfanyl, tetrasulfanyl and pentasulfanyl HSSSSS<sup>•</sup>. S<sup>−</sup>* is termed sulfanidyl.
HS<sup>+</sup> is known as sulfanylium, and the common [[hydrosulfide ion]] HS<sup>−</sup> is also known as sulfanido for a ligand or sulfanide as an anion.  Further down the periodic table, HSe<sup>•</sup> is known as selanyl, and HTe<sup>•</sup> is termed tellanyl.

==References==

{{Reflist|40em}}

==External links==
*[http://webbook.nist.gov/cgi/cbook.cgi?ID=C13940211&Mask=1 Mercapto radical] from NIST
*{{cite journal|last=Milan|first=J. B.|author2=W. J. Buma |author3=C. A. de Lange |date=22 October 1996|title=Two-photon resonance enhanced multiphoton ionization photoelectron spectroscopy of the SH (SD) radical below and above the lowest ionization threshold|journal=Journal of Chemical Physics|volume=105|issue=16|pages=6688–6712|url=https://pure.uva.nl/ws/files/1936641/1527_JChPh_1996_105_16_6688.pdf|access-date=11 October 2011|doi=10.1063/1.471850|bibcode=1996JChPh.105.6688M|s2cid=52094387 }}
*{{cite journal|last=Burma|first=W.J.|author2=J. B. Milan |author3=C.A. de Lange |author4=C. M. Western. |author5=N.M.R. Ashfold |year=1995|title=Two-photon resonance enhanced MPI-PES above the lowest ionization threshold: observation of the [a E<sup>1</sup>delta]5p pi E<sup>2</sup>phi state of the SH (SD) radical|journal=Chemical Physics Letters|volume=239|issue=4–6|pages=326–331|url=https://pure.uva.nl/ws/files/2012241/28655_ChPhL_1995_239_326.pdf|doi=10.1016/0009-2614(95)00488-P|bibcode=1995CPL...239..326M}}
*{{cite thesis|url=https://open.library.ubc.ca/media/stream/pdf/24/1.0166493/1|title=Manipulation of the motion of polyatomic molecules by AC and DC Stark deceleration|date=August 2015|publisher=THE UNIVERSITY OF BRITISH COLUMBIA|first1=Omid|last1=Nourbakhsh|location=Vancouver}} Sulfur deuteride radical SD• microwave spectrum
{{Molecules detected in outer space}}
{{Hydrides by group}}

[[Category:Hydrides]]
[[Category:Sulfur compounds]]