The Collaborative International Dictionary of English v.0.48:

Persulphocyanogen \Per*sul`pho*cy*an"o*gen\, n. (Chem.)
   An orange-yellow substance, produced by the action of
   chlorine or boiling dilute nitric acid and sulphocyanate of
   potassium; -- called also pseudosulphocyanogen,
   perthiocyanogen, and formerly sulphocyanogen.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sulphocyanogen \Sul`pho*cy*an"o*gen\, n. (Chem.)
   See Persulphocyanogen. [Obs.]
   [1913 Webster]