Tellurium Diselenocyanate

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. 

All tellurium derivatives with exception of the diorgano tellurium diselenocyanates have infrared absorption bands in the regions that would indicate N—Te bonding. The frequencies for v(c—Se) in the diorgano tellurium selenocyanates (598 cm- ) fall between the frequencies for organic iso selenocyanates (630 + 20 cm-1) and those for normal selenocyanates (550-520 cm- ). 

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