Tellurium Bis selenocyanate

Diorgano tellurium dihalides stirred with silver selenocyanate or potassium selenocyanate in chloroform or acetone produce diorgano tellurium bis[selenocyanates] 3. 

Tellurium diselenocyanate is only known in the form of its complexes with thioureas4- s. The complexes were prepared from the corresponding bis[thiourea]tellurium dibromides and excess potassium selenocyanate in warm methanol. Cooling the filtrate produced light brown crystals that were stable when dry and liberated tellurium on contact with water. 

Phenyl tellurium halides, generated from diphenyl ditellurium and halogen in the presence or absence of thiourea, reacted with potassium selenocyanate to give bis[phenyltelluro] selenium3. 

A similar exchange reaction produced the 1 1 complexes of phenyl tellurium thiocyanate with ethylenethiourea1, when the phenyl tellurium chloride complex was treated with potassium thiocyanate in aqueous methanol. However, the phenyl tellurium chloride -selenourea adduct and potassium selenocyanate yielded bis[phenyIteUuro] selenium3. Phosphane selenides also coordinate to phenyl tellurium halides3. 

---