An improved method for generating thiocyanogen entails oxidation of plumbous thiocyanate, which precipitates when aqueous solutions of lead ( II ) nitrate and sodium thiocyanate are combined.
2.
Thiocyanogen was originally prepared by the reaction of iodine with a suspension of silver thiocyanate in diethyl ether, but this reaction suffers from competing equilibria attributed to the weak oxidizing power of iodine.
3.
A suspension of anhydrous Pb ( SCN ) 2 is treated with bromine in glacial acetic acid to afford a 0.1M solution of thiocyanogen that is stable for days . Alternatively, a solution of bromine in methylene chloride is added dropwise to a suspension of Pb ( SCN ) 2 in methylene chloride at 0 �C followed by filtration under argon to give a solution of thiocyanogen that should be used immediately.
4.
A suspension of anhydrous Pb ( SCN ) 2 is treated with bromine in glacial acetic acid to afford a 0.1M solution of thiocyanogen that is stable for days . Alternatively, a solution of bromine in methylene chloride is added dropwise to a suspension of Pb ( SCN ) 2 in methylene chloride at 0 �C followed by filtration under argon to give a solution of thiocyanogen that should be used immediately.
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