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Thiocyanogen
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<h2 id="history">History</h2> <p><a href="/facts/Berzelius/HakSv3sP">Berzelius</a> first proposed that thiocyanogen ought exist as part of his <a href="/facts/Radical_theory/7j9kM2zC">radical theory</a>, but the compound's isolation proved problematic. <a href="/facts/Liebig/0vKzMlDA">Liebig</a> pursued a wide variety of synthetic routes for the better part of a century, but, even with <a href="/facts/W%25C3%25B6hler/p6PwQoDc">Wöhler</a>'s assistance, only succeeded in producing a complex mixture with the <a href="/facts/Empirical_formula/xd0vSIlm">proportions</a> of thiocyanic acid. In 1861, Linnemann generated appreciable quantities of thiocyanogen from a <a href="/facts/Silver_thiocyanate/XwY1fcVF">silver thiocyanate</a> <a href="/facts/Suspension_(mixture)/S3xp96TL">suspension</a> in <a href="/facts/Diethyl_ether/Ep20vEdj">diethyl ether</a> and excess <a href="/facts/Iodine/JlfMecMf">iodine</a>, but misidentified the minor product as sulfur iodide cyanide (ISCN).<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> Indeed, that reaction suffers from competing <a href="/facts/Dynamic_equilibrium/jKq8wjyu">equilibria</a> attributed to the weak oxidizing power of iodine; the major product is <a href="/facts/Sulfur_dicyanide/PDeuy8px">sulfur dicyanide</a>.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a> The following year, Schneider produced thiocyangen from silver thiocyanate and <a href="/facts/Disulfur_dichloride/aYBYJprF">disulfur dichloride</a>, but the product <a href="/facts/Disproportionation/67QMkXrV">disproportionated</a> to sulfur and trisulfur dicyanides.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a> </p><p>The subject then lay fallow until the <a href="/facts/1910s/bcEIRTdF">1910s</a>, when <a href="/facts/Niels_Bjerrum/Ga8c5IFf">Niels Bjerrum</a> began investigating gold thiocyanate complexes. Some <a href="/facts/Reductive_elimination/H2SXpH0n">eliminated reductively</a> and <a href="/facts/Reversible_reaction/V3Afejgb">reversibly</a>, whereas others appeared to irreversibly generate <a href="/facts/Cyanide/t0o8FMKI">cyanide</a> and <a href="/facts/Sulfate/yuWVxsUf">sulfate</a> salt solutions. Understanding the process required reanalyzing the decomposition of thiocyanogen using the then-new techniques of <a href="/facts/Physical_chemistry/WqwnJjRM">physical chemistry</a>. Bjerrum's work revealed that <a href="/facts/Oxidane/FFsl65l1">water</a> catalyzed thiocyanogen's decomposition via <a href="/facts/Hypothiocyanous_acid/MB40CyvG">hypothiocyanous acid</a>. Moreover, the <a href="/facts/Oxidation_potential/PqpNUgSl">oxidation potential</a> of thiocyanogen appeared to be 0.769 <a href="/facts/Volts/KF18MXP2">V</a>, slightly greater than <a href="/facts/Iodine/JlfMecMf">iodine</a> but less than <a href="/facts/Bromine/oLfj3C7D">bromine</a>.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a> In 1919, Söderbäck successfully isolated stable thiocyanogen from oxidation of <a href="/facts/Oxidation/Pyd5RVcj">oxidation</a> of plumbous thiocyanate with bromine.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a><a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> </p> <h2 id="preparation">Preparation</h2> <p>Modern syntheses typically differ little from Söderbäck's process. Thiocyanogen synthesis begins when aqueous solutions of <a href="/facts/Lead(II)_nitrate/k2494KxQ">lead(II) nitrate</a> and <a href="/facts/Sodium_thiocyanate/n6MV4kLJ">sodium thiocyanate</a>, combined, precipitate plumbous thiocyanate. Treating an anhydrous Pb(SCN)2 suspension in <a href="/facts/Glacial_acetic_acid/uyBKA2Pd">glacial acetic acid</a> with bromine then affords a 0.1M solution of thiocyanogen that is stable for days.<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> Alternatively, a solution of bromine in methylene chloride is added to a suspension of Pb(SCN)2 in methylene chloride at 0 °C.<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a> </p> Pb(SCN)2 + Br2 → (SCN)2 + PbBr2 <p>In either case, the oxidation is <a href="/facts/Exothermic/gCuSvpa4">exothermic</a>.<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a>: 255 </p><p>An alternative technique is the <a href="/facts/Thermal_decomposition/Qqx9RqkW">thermal decomposition</a> of <a href="/facts/Cupric_thiocyanate/RRKgQ3j7">cupric thiocyanate</a> at 35–80 °C:<a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a>: 253 </p> 2Cu(SCN)2 → 2 CuSCN + (SCN)2 <h2 id="reactions">Reactions</h2> <p>In general, thiocyanogen is stored in solution, as the pure compound explodes above 20 °C<a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a> to a red-orange <a href="/facts/Polymer/eF32E50K">polymer</a>.<a class="footnote-ref" id="fnref:16" href="#fn:16"><sup>16</sup></a>: 241 However, the sulfur atoms disproportionate in water:<a class="footnote-ref" id="fnref:17" href="#fn:17"><sup>17</sup></a>: 241–242 <a class="footnote-ref" id="fnref:18" href="#fn:18"><sup>18</sup></a> </p> 3(SCN)2 + 4H2O → H2SO4 + HCN + 5HSCN <p>Thiocyanogen is a weak <a href="/facts/Electrophile/1AHFg1zm">electrophile</a>, attacking only highly <a href="/facts/Electrophilic_aromatic_directing_groups/CK4GNCWH">activated</a> (<a href="/facts/Phenols/xs1CtNTa">phenolic</a> or anilinic) or <a href="/facts/Polycyclic_aromatic_hydrocarbon/K52xSfNC">polycyclic</a> arenes.<a class="footnote-ref" id="fnref:19" href="#fn:19"><sup>19</sup></a>: 243–245 It <a href="/facts/Carbonyl_%25CE%25B1-substitution_reactions/LwvLVtys">attacks carbonyls at the α position</a>.<a class="footnote-ref" id="fnref:20" href="#fn:20"><sup>20</sup></a> Heteratoms are attacked more easily, and the compound thiocyanates <a href="/facts/Sulfur/IK0amTfM">sulfur</a>, <a href="/facts/Nitrogen/Nf1QpGDz">nitrogen</a>, and various <a href="/facts/Poor_metal/wjp3aeGn">poor metals</a>.<a class="footnote-ref" id="fnref:21" href="#fn:21"><sup>21</sup></a>: 241 Thiocyanogen solutions in <a href="/facts/Nonpolar_solvent/LoMPMz8S">nonpolar solvents</a> react almost completely with <a href="/facts/Chlorine/y27UwYBM">chlorine</a> to give chlorine thiocyanate; but the corresponding bromine thiocyanate is unstable above −50 °C, forming polymeric thiocyanogen and <a href="/facts/Bromine/oLfj3C7D">bromine</a>.<a class="footnote-ref" id="fnref:22" href="#fn:22"><sup>22</sup></a> </p><p>The compound adds <i>trans</i> to alkenes to give 1,2-bis(thiocyanato) compounds; the intermediate thiiranium ion can be trapped with many nucleophiles.<a class="footnote-ref" id="fnref:23" href="#fn:23"><sup>23</sup></a> <a href="/facts/Radical_polymerization/CbG5UqAd">Radical polymerization</a> is the most likely side-reaction, and yields improve when cold and dark.<a class="footnote-ref" id="fnref:24" href="#fn:24"><sup>24</sup></a><a class="footnote-ref" id="fnref:25" href="#fn:25"><sup>25</sup></a>: 247 However, the <a href="/facts/Addition_reaction/LvIngK0g">addition reaction</a> is slow, and light may be necessary to accelerate the process.<a class="footnote-ref" id="fnref:26" href="#fn:26"><sup>26</sup></a>: 247 Titanacyclopentadienes give (<i>Z</i>,<i>Z</i>)-1,4-bis(thiocyanato)-1,3-butadienes, which in turn can be converted to 1,2-<a href="/facts/Dithiin/M3XclqRs">dithiins</a>.<a class="footnote-ref" id="fnref:27" href="#fn:27"><sup>27</sup></a> Thiocyanogen only adds once to <a href="/facts/Alkyne/VHI4N5Wo">alkynes</a>; the resulting dithioacyloin dicyanate is not particularly olefinic.<a class="footnote-ref" id="fnref:28" href="#fn:28"><sup>28</sup></a>: 247 </p><p>Selenocyanogen, (SeCN)2, prepared from reaction of silver selenocyanate with iodine in <a href="/facts/Tetrahydrofuran/P5t6SkMK">tetrahydrofuran</a> at 0 °C,<a class="footnote-ref" id="fnref:29" href="#fn:29"><sup>29</sup></a> reacts in a similar manner to thiocyanogen.<a class="footnote-ref" id="fnref:30" href="#fn:30"><sup>30</sup></a> </p> <h2 id="applications">Applications</h2> <p>Thiocyanogen has been used to estimate the <a href="/facts/Degree_of_unsaturation/w6PoaWAX">degree of unsaturation</a> in <a href="/facts/Fatty_acids/JGg3erIu">fatty acids</a>, similar to the <a href="/facts/Iodine_value/fU5LMT9V">iodine value</a>.<a class="footnote-ref" id="fnref:31" href="#fn:31"><sup>31</sup></a><a class="footnote-ref" id="fnref:32" href="#fn:32"><sup>32</sup></a>: 247 </p> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Schwan, Adrian L. (2001-04-15), "Thiocyanogen", Encyclopedia of Reagents for Organic Synthesis, Chichester, UK: John Wiley & Sons, Ltd, doi:10.1002/047084289x.rt095, ISBN 978-0-471-93623-7, retrieved 2024-03-30 <a href="978-0-471-93623-7" target="_blank">978-0-471-93623-7</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Jensen, James (2005). "Vibrational frequencies and structural determination of thiocyanogen". Journal of Molecular Structure: THEOCHEM. 714 (2–3): 137–141. doi:10.1016/j.theochem.2004.09.046. <a href="https://zenodo.org/record/1259391" target="_blank">https://zenodo.org/record/1259391</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Aune, Thomas M.; Thomas, Edwin L. (1977) [2 May 1977]. "Accumulation of hypothiocyanite ion during peroxidase-catalyzed oxidation of thiocyanate ion". European Journal of Biochemistry. 80: 209–214. doi:10.1111/j.1432-1033.1977.tb11873.x. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Lemma, Kelemu; Ashby, Michael T. (2009-09-21). "Reactive Sulfur Species: Kinetics and Mechanism of the Reaction of Hypothiocyanous Acid with Cyanide To Give Dicyanosulfide in Aqueous Solution". Chemical Research in Toxicology. 22 (9): 1622–1628. doi:10.1021/tx900212r. ISSN 0893-228X. <a href="https://pubs.acs.org/doi/10.1021/tx900212r" target="_blank">https://pubs.acs.org/doi/10.1021/tx900212r</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Kaufmann, H. P. (1925). "Das freie Rhodan und seine Anwendung in der Maßanalyse. Eine neue Kennzahl der Fette" [Unbound rhodanium and its application to elemental analysis: A new measurement technique for fats]. Archiv der Pharmazie und Berichte der Deutschen Pharmazeutischen Gesellschaft (in German). 263: 675–721 – via HathiTrust. <a href="https://babel.hathitrust.org/cgi/pt?id=uc1.b3706518" target="_blank">https://babel.hathitrust.org/cgi/pt?id=uc1.b3706518</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Söderbäck, Erik (1919). "Studien über das freie Rhodan". Justus Liebig's Annalen der Chemie. 419 (3): 217–322. doi:10.1002/jlac.19194190302. hdl:2027/uc1.$b133351. <a href="https://zenodo.org/record/1427649" target="_blank">https://zenodo.org/record/1427649</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Kaufmann, H. P. (1925). "Das freie Rhodan und seine Anwendung in der Maßanalyse. Eine neue Kennzahl der Fette" [Unbound rhodanium and its application to elemental analysis: A new measurement technique for fats]. Archiv der Pharmazie und Berichte der Deutschen Pharmazeutischen Gesellschaft (in German). 263: 675–721 – via HathiTrust. <a href="https://babel.hathitrust.org/cgi/pt?id=uc1.b3706518" target="_blank">https://babel.hathitrust.org/cgi/pt?id=uc1.b3706518</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>Kaufmann, H. P. (1925). "Das freie Rhodan und seine Anwendung in der Maßanalyse. Eine neue Kennzahl der Fette" [Unbound rhodanium and its application to elemental analysis: A new measurement technique for fats]. Archiv der Pharmazie und Berichte der Deutschen Pharmazeutischen Gesellschaft (in German). 263: 675–721 – via HathiTrust. <a href="https://babel.hathitrust.org/cgi/pt?id=uc1.b3706518" target="_blank">https://babel.hathitrust.org/cgi/pt?id=uc1.b3706518</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>Kaufmann, H. P. (1925). "Das freie Rhodan und seine Anwendung in der Maßanalyse. Eine neue Kennzahl der Fette" [Unbound rhodanium and its application to elemental analysis: A new measurement technique for fats]. Archiv der Pharmazie und Berichte der Deutschen Pharmazeutischen Gesellschaft (in German). 263: 675–721 – via HathiTrust. <a href="https://babel.hathitrust.org/cgi/pt?id=uc1.b3706518" target="_blank">https://babel.hathitrust.org/cgi/pt?id=uc1.b3706518</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>Söderbäck, Erik (1919). "Studien über das freie Rhodan". Justus Liebig's Annalen der Chemie. 419 (3): 217–322. doi:10.1002/jlac.19194190302. hdl:2027/uc1.$b133351. <a href="https://zenodo.org/record/1427649" target="_blank">https://zenodo.org/record/1427649</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>Gardner, William Howlett; Weinberger, Harold (1939). "Thiocyanogen Solution". Inorganic Syntheses. Inorganic Syntheses. Vol. 1. pp. 84–86. doi:10.1002/9780470132326.ch29. ISBN 978-0-470-13232-6. {{cite book}}: ISBN / Date incompatibility (help) <a href="978-0-470-13232-6" target="_blank">978-0-470-13232-6</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>Block, E; Birringer, M; DeOrazio, R; Fabian, J; Glass, RS; Guo, C; He, C; Lorance, E; Qian, Q; Schroeder, TB; Shan, Z; Thiruvazhi, M; Wilson, GC; Zhang, Z (2000). "Synthesis, Properties, Oxidation, and Electrochemistry of 1,2-Dichalcogenins". J. Am. Chem. Soc. 122 (21): 5052–5064. doi:10.1021/ja994134s. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> <li id="fn:13"><p>Wood, John L. (August 1947) [1946]. "Substitution and addition reactions of thiocyanogen". In Adams, Roger (ed.). Organic Reactions (PDF). Vol. 3 (3rd reprint ed.). New York / London: Wiley / Chapman Hall. pp. 241–266. <a href="http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246" target="_blank">http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li> <li id="fn:14"><p>Wood, John L. (August 1947) [1946]. "Substitution and addition reactions of thiocyanogen". In Adams, Roger (ed.). Organic Reactions (PDF). Vol. 3 (3rd reprint ed.). New York / London: Wiley / Chapman Hall. pp. 241–266. <a href="http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246" target="_blank">http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></p></li> <li id="fn:15"><p>Schwan, Adrian L. (2001-04-15), "Thiocyanogen", Encyclopedia of Reagents for Organic Synthesis, Chichester, UK: John Wiley & Sons, Ltd, doi:10.1002/047084289x.rt095, ISBN 978-0-471-93623-7, retrieved 2024-03-30 <a href="978-0-471-93623-7" target="_blank">978-0-471-93623-7</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></p></li> <li id="fn:16"><p>Wood, John L. (August 1947) [1946]. "Substitution and addition reactions of thiocyanogen". In Adams, Roger (ed.). Organic Reactions (PDF). Vol. 3 (3rd reprint ed.). New York / London: Wiley / Chapman Hall. pp. 241–266. <a href="http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246" target="_blank">http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></p></li> <li id="fn:17"><p>Wood, John L. (August 1947) [1946]. "Substitution and addition reactions of thiocyanogen". In Adams, Roger (ed.). Organic Reactions (PDF). Vol. 3 (3rd reprint ed.). New York / London: Wiley / Chapman Hall. pp. 241–266. <a href="http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246" target="_blank">http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></p></li> <li id="fn:18"><p>Stedman, G.; Whincup, P. A. E. (1969). "Oxidation of metal thiocyanates by nitric and nitrous acids. Part I. Products". Journal of the Chemical Society A: Inorganic, Physical, Theoretical: 1145. doi:10.1039/j19690001145. ISSN 0022-4944. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></p></li> <li id="fn:19"><p>Wood, John L. (August 1947) [1946]. "Substitution and addition reactions of thiocyanogen". In Adams, Roger (ed.). Organic Reactions (PDF). Vol. 3 (3rd reprint ed.). New York / London: Wiley / Chapman Hall. pp. 241–266. <a href="http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246" target="_blank">http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246</a> <a href="#fnref:19" class="footnote-back-ref">↩</a></p></li> <li id="fn:20"><p>Wood, John L. (August 1947) [1946]. "Substitution and addition reactions of thiocyanogen". In Adams, Roger (ed.). Organic Reactions (PDF). Vol. 3 (3rd reprint ed.). New York / London: Wiley / Chapman Hall. pp. 241–266. <a href="http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246" target="_blank">http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246</a> <a href="#fnref:20" class="footnote-back-ref">↩</a></p></li> <li id="fn:21"><p>Wood, John L. (August 1947) [1946]. "Substitution and addition reactions of thiocyanogen". In Adams, Roger (ed.). Organic Reactions (PDF). Vol. 3 (3rd reprint ed.). New York / London: Wiley / Chapman Hall. pp. 241–266. <a href="http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246" target="_blank">http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246</a> <a href="#fnref:21" class="footnote-back-ref">↩</a></p></li> <li id="fn:22"><p>Magee, Philip S. (1971). "The Sulfur–Bromine Bond". In Senning, Alexander (ed.). Sulfur in Organic and Inorganic Chemistry. Vol. 1. New York: Marcel Dekker. pp. 269–270. ISBN 0-8247-1615-9. LCCN 70-154612. <a href="0-8247-1615-9" target="_blank">0-8247-1615-9</a> <a href="#fnref:22" class="footnote-back-ref">↩</a></p></li> <li id="fn:23"><p>Schwan, Adrian L. (2001-04-15), "Thiocyanogen", Encyclopedia of Reagents for Organic Synthesis, Chichester, UK: John Wiley & Sons, Ltd, doi:10.1002/047084289x.rt095, ISBN 978-0-471-93623-7, retrieved 2024-03-30 <a href="978-0-471-93623-7" target="_blank">978-0-471-93623-7</a> <a href="#fnref:23" class="footnote-back-ref">↩</a></p></li> <li id="fn:24"><p>Schwan, Adrian L. (2001-04-15), "Thiocyanogen", Encyclopedia of Reagents for Organic Synthesis, Chichester, UK: John Wiley & Sons, Ltd, doi:10.1002/047084289x.rt095, ISBN 978-0-471-93623-7, retrieved 2024-03-30 <a href="978-0-471-93623-7" target="_blank">978-0-471-93623-7</a> <a href="#fnref:24" class="footnote-back-ref">↩</a></p></li> <li id="fn:25"><p>Wood, John L. (August 1947) [1946]. "Substitution and addition reactions of thiocyanogen". In Adams, Roger (ed.). Organic Reactions (PDF). Vol. 3 (3rd reprint ed.). New York / London: Wiley / Chapman Hall. pp. 241–266. <a href="http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246" target="_blank">http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246</a> <a href="#fnref:25" class="footnote-back-ref">↩</a></p></li> <li id="fn:26"><p>Wood, John L. (August 1947) [1946]. "Substitution and addition reactions of thiocyanogen". In Adams, Roger (ed.). Organic Reactions (PDF). Vol. 3 (3rd reprint ed.). New York / London: Wiley / Chapman Hall. pp. 241–266. <a href="http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246" target="_blank">http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246</a> <a href="#fnref:26" class="footnote-back-ref">↩</a></p></li> <li id="fn:27"><p>Block, E; Birringer, M; DeOrazio, R; Fabian, J; Glass, RS; Guo, C; He, C; Lorance, E; Qian, Q; Schroeder, TB; Shan, Z; Thiruvazhi, M; Wilson, GC; Zhang, Z (2000). "Synthesis, Properties, Oxidation, and Electrochemistry of 1,2-Dichalcogenins". J. Am. Chem. Soc. 122 (21): 5052–5064. doi:10.1021/ja994134s. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:27" class="footnote-back-ref">↩</a></p></li> <li id="fn:28"><p>Wood, John L. (August 1947) [1946]. "Substitution and addition reactions of thiocyanogen". In Adams, Roger (ed.). Organic Reactions (PDF). Vol. 3 (3rd reprint ed.). New York / London: Wiley / Chapman Hall. pp. 241–266. <a href="http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246" target="_blank">http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246</a> <a href="#fnref:28" class="footnote-back-ref">↩</a></p></li> <li id="fn:29"><p>Meinke, PT; Krafft, GA; Guram, A (1988). "Synthesis of selenocyanates via cyanoselenation of organocopper reagents". J. Org. Chem. 53 (15): 3632–3634. doi:10.1021/jo00250a047. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:29" class="footnote-back-ref">↩</a></p></li> <li id="fn:30"><p>Block, E; Birringer, M; DeOrazio, R; Fabian, J; Glass, RS; Guo, C; He, C; Lorance, E; Qian, Q; Schroeder, TB; Shan, Z; Thiruvazhi, M; Wilson, GC; Zhang, Z (2000). "Synthesis, Properties, Oxidation, and Electrochemistry of 1,2-Dichalcogenins". J. Am. Chem. Soc. 122 (21): 5052–5064. doi:10.1021/ja994134s. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:30" class="footnote-back-ref">↩</a></p></li> <li id="fn:31"><p>Kaufmann, H. P. (1925). "Das freie Rhodan und seine Anwendung in der Maßanalyse. Eine neue Kennzahl der Fette" [Unbound rhodanium and its application to elemental analysis: A new measurement technique for fats]. Archiv der Pharmazie und Berichte der Deutschen Pharmazeutischen Gesellschaft (in German). 263: 675–721 – via HathiTrust. <a href="https://babel.hathitrust.org/cgi/pt?id=uc1.b3706518" target="_blank">https://babel.hathitrust.org/cgi/pt?id=uc1.b3706518</a> <a href="#fnref:31" class="footnote-back-ref">↩</a></p></li> <li id="fn:32"><p>Wood, John L. (August 1947) [1946]. "Substitution and addition reactions of thiocyanogen". In Adams, Roger (ed.). Organic Reactions (PDF). Vol. 3 (3rd reprint ed.). New York / London: Wiley / Chapman Hall. pp. 241–266. <a href="http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246" target="_blank">http://chemistry-chemists.com/chemister/Polytom-English/organic-reactions/organic-reactions-03-1946.pdf#page=246</a> <a href="#fnref:32" class="footnote-back-ref">↩</a></p></li> </ol>