From Tetraalkoxy Tellurium Compounds

Fluorination of tetraalkoxy tellurium derivatives with a fluorine/nitrogen gas mixture in a medium of fluorotrichloromethane at —78° produced several alkoxy tellurium fluorides that could not be separated by distillation F-NMR spectroscopy was used to identify the products and to determine their relative concentrations. 

Agranat, M. Rabinoviiz, H. Selig, Inorg. Nucl. Chem. Lett. 11, 185 (1975). 

Tetraalkoxy Tellurium Difluorides 5 g of tetraalkoxy tellurium are placed in a conical flask in a dry box, and the vessel is then conneeted to a vacuum line, cooled to —78°, and 20 ml of fluorotrichloromethane are condensed into the vessel. The mixture is vigorously stirred at —78° and a stream of fluorine diluted with 4 parts of nitrogen is passed over the mixture for 3 h, thus providing a four-fold excess of fluorine. The apparatus is then purged with nitrogen, fluorotrichloromethane is allowed to evaporate, and the residue is extracted with chloroform. The chloroform is evaporated and the residue is distilled under vacuum. 

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