Hydrogen disulfide

<h2 id="structure">Structure</h2>
The connection of atoms in the hydrogen disulfide molecule is H−S−S−H. The structure of hydrogen disulfide is similar to that of <a href="/facts/Hydrogen_peroxide/vju6HBIc">hydrogen peroxide</a>, with C2 <a href="/facts/Symmetry_group/CNqeseMp">point group symmetry</a>. Both molecules are distinctly nonplanar. The <a href="/facts/Dihedral_angle/C9WEJsuS">dihedral angle</a> between the Ha−S−S and S−S−Hb planes is 90.6°, compared with 111.5° in H2O2. The H−S−S bond angle is 92°, close to 90° for unhybridized divalent sulfur.<a class="footnote-ref" id="fnref:2" href="#fn:2">2</a>

<h2 id="synthesis">Synthesis</h2>
Hydrogen disulfide can be synthesised by <a href="/facts/Cracking_(chemistry)/EBLtwW4g">cracking</a> <a href="/facts/Polysulfane/FAGqzw4I">polysulfanes</a> (H2Sn) according to this idealized equation:

H2Sn → H2S2 + Sn−2
The main impurity is trisulfane (H2S3).<a class="footnote-ref" id="fnref:3" href="#fn:3">3</a> The precursor polysulfane is produced by the reaction of <a href="/facts/Hydrochloric_acid/HqItJlUT">hydrochloric acid</a> with aqueous <a href="/facts/Sodium_polysulfide/ExyYvKfR">sodium polysulfide</a>. The polysulfane precipitates as an oil.<a class="footnote-ref" id="fnref:4" href="#fn:4">4</a><a class="footnote-ref" id="fnref:5" href="#fn:5">5</a>

<h2 id="reactions">Reactions</h2>
Upon contact with water or <a href="/facts/Alcohol_(chemistry)/Y0SCTDkh">alcohols</a>, hydrogen disulfide readily decomposes under ambient conditions to <a href="/facts/Hydrogen_sulfide/UbCqjMMk">hydrogen sulfide</a> and sulfur. 
It is more acidic than <a href="/facts/Hydrogen_sulfide/UbCqjMMk">hydrogen sulfide</a>, but the pKa has not been reported.<a class="footnote-ref" id="fnref:6" href="#fn:6">6</a>
In <a href="/facts/Organosulfur_chemistry/sUxSSXwD">organosulfur chemistry</a>, hydrogen disulfide adds to <a href="/facts/Alkene/RtYcS6kU">alkenes</a> to give <a href="/facts/Disulfide/eDx5Xtlg">disulfides</a> and <a href="/facts/Thiol/VemKEDP9">thiols</a>.<a class="footnote-ref" id="fnref:7" href="#fn:7">7</a>

<h2 id="quantum-tunneling-and-its-suppression-in-deuterium-disulfide">Quantum tunneling and its suppression in deuterium disulfide</h2>
The <a href="/facts/Deuterium/Bv4wfCkw">deuterated</a> form of hydrogen disulfide, deuterium disulfide D−S−S−D (dideuterodisulfane), has a similar geometry to H−S−S−H, but its tunneling time is slower, making it a convenient test case for the <a href="/facts/Quantum_Zeno_effect/LQ2luyoy">quantum Zeno effect</a>, in which frequent observation of a quantum system suppresses its normal evolution. Trost and Hornberger<a class="footnote-ref" id="fnref:8" href="#fn:8">8</a> have calculated that while an isolated D−S−S−D molecule would spontaneously oscillate between left and right chiral forms with a period of 5.6 milliseconds, the presence of a small amount of inert helium gas should stabilize the chiral states, the collisions of the helium atoms in effect "observing" the molecule's momentary <a href="/facts/Chirality/hjx0eGrB">chirality</a> and so suppressing spontaneous evolution to the other chiral state.<a class="footnote-ref" id="fnref:9" href="#fn:9">9</a>

<h2 id="health-effects">Health effects</h2>
In high concentrations, it can cause dizziness, disorientation and ultimately unconsciousness.<a class="footnote-ref" id="fnref:10" href="#fn:10">10</a>

<h2 id="historic-literature">Historic literature</h2>
<ul><li>Walton, James H.; Parsons, Llewellyn B. (1921-12-01). <a href="https://zenodo.org/record/1428820">"Preparation and Properties of the Persulfides of Hydrogen"</a>. J. Am. Chem. Soc. 43 (12): 2539–48. <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1021%2Fja01445a008">10.1021/ja01445a008</a>.</li>
<li>Georg Brauer: Handbook of Preparative Inorganic Chemistry Volume I, page 391, Wiley, 1963.</li>
<li>von Richter, Victor: Translated by Edgar F Smith, "A Text-Book of Inorganic Chemistry", Page 111, P. Blakiston, Son & Co., 1893</li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1">Steudel, Ralf (2003). "Inorganic Polysulfanes H2Sn with n > 1". Topic in Current Chemistry. Topics in Current Chemistry. Vol. 231. pp. 99–126. doi:10.1007/b13182. ISBN 978-3-540-40378-4. <a href="978-3-540-40378-4" target="_blank">978-3-540-40378-4</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></li>
<li id="fn:2">Steudel, Ralf (2003). "Inorganic Polysulfanes H2Sn with n > 1". Topic in Current Chemistry. Topics in Current Chemistry. Vol. 231. pp. 99–126. doi:10.1007/b13182. ISBN 978-3-540-40378-4. <a href="978-3-540-40378-4" target="_blank">978-3-540-40378-4</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">Steudel, Ralf (2003). "Inorganic Polysulfanes H2Sn with n > 1". Topic in Current Chemistry. Topics in Current Chemistry. Vol. 231. pp. 99–126. doi:10.1007/b13182. ISBN 978-3-540-40378-4. <a href="978-3-540-40378-4" target="_blank">978-3-540-40378-4</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">Steudel, Ralf (2003). "Inorganic Polysulfanes H2Sn with n > 1". Topic in Current Chemistry. Topics in Current Chemistry. Vol. 231. pp. 99–126. doi:10.1007/b13182. ISBN 978-3-540-40378-4. <a href="978-3-540-40378-4" target="_blank">978-3-540-40378-4</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">De, A. K. (2001-01-15). A Text Book of Inorganic Chemistry. Imperial College Press. ISBN 978-81-224-1384-7. <a href="978-81-224-1384-7" target="_blank">978-81-224-1384-7</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">Steudel, Ralf (2003). "Inorganic Polysulfanes H2Sn with n > 1". Topic in Current Chemistry. Topics in Current Chemistry. Vol. 231. pp. 99–126. doi:10.1007/b13182. ISBN 978-3-540-40378-4. <a href="978-3-540-40378-4" target="_blank">978-3-540-40378-4</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
<li id="fn:7">Hazardous Reagents, Robinson Brothers <a href="http://www.rbltd.co.uk/?PAGEID=10520" target="_blank">http://www.rbltd.co.uk/?PAGEID=10520</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></li>
<li id="fn:8">Trost, J.; Hornberger, K. (2009). "Hund's Paradox and the Collisional Stabilization of Chiral Molecules". Phys. Rev. Lett. 103 (2): 023202. arXiv:0811.2140. Bibcode:2009PhRvL.103b3202T. doi:10.1103/PhysRevLett.103.023202. PMID 19659202. <a href="/wiki/ArXiv_(identifier)" target="_blank">/wiki/ArXiv_(identifier)</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></li>
<li id="fn:9">Month-long calculation solves 82-year-old quantum paradox, Physics Today, September 2009, p. 16 <a href="https://www.uni-due.de/~hp0198/pubs/physicstoday_cday.pdf" target="_blank">https://www.uni-due.de/~hp0198/pubs/physicstoday_cday.pdf</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></li>
<li id="fn:10">Stein, Wilkinson, G (2007). Seminars in general adult psychiatry. Royal College of Psychiatrists. ISBN 978-1-904671-44-2. <a href="978-1-904671-44-2" target="_blank">978-1-904671-44-2</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></li>
</ol>

Hydrogen disulfide open-in-new

Hydrogen disulfide