Tantalum pentiodide

Definite compounds of niobium and iodine are unknown, although tantalum pentiodide and vanadium tri-iodide have been prepared. 

Tantalum Pentiodide, Tal5, has been obtained by distilling tantalum pentabromide in a stream of dry hydrogen iodide and purifying the product by redistilling it in an atmosphere of carbon dioxide. It is an almost black substance which melts to a brown liquid, and is decomposed by water similarly to the pentabromide, but not so vigorously. 

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