From Alkali Metal Ditellurides

Lithium ditelluride, prepared from tellurium and lithium triethylborohydride in tetrahy-drofuran, reacted with a,o)-dibromoalkanes to produce polymeric polymethylene ditellurium compounds  

Polyfdecamethylene Ditellurium) A solution of lithium ditelluride in tetrahydrofuran is prepared from 

02 g (8 mmol) of tellurium powder and 0.85 g (8 mmol) of lithium triethylborohydride under dry nitrogen . The mixture is agitated using ultrasound. When all the tellurium has reacted, a nitrogen-purged solution of 

2 g (4 mmol) of 1,10-dibromodecane is added dropwise to the dark red lithium ditelluride solution. The mixture is stirred for 30 min, and the precipitate is filtered, washed with water, and then with tetrahydrofuran. The solid is dissolved in carbon disulfide, diethyl ether is added to the solution to precipitate the polymer, and the dissolution-precipitation procedure is repeated once more. The product is filtered and dried under vacuum at 20 yield 1.25 g (79%). 

Elemental tellurium can be removed by stirring the polymer in an aqueous solution of potassium cyanide for several hours . 

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Fluorine is the most electronegative of all the elements, so that the bonds it forms with most other elements have considerable ionic character. With the exception of the alkali halides most crystalline fluorides have structures different from those of the other halides of the same metal. A number of difluorides and dioxides have the same crystal structure, whereas the corresponding dichlorides, dibromides, and diiodides have in many cases structures similar to those of disulphides, diselenides, and ditellurides. The extreme electronegativity of fluorine enables it to form much stronger hydrogen bonds than any other element, resulting in the abnormal properties of HF as compared with the other acids HX, the much... 

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