Tellurium Tetrachloride TeCl

With chlorine and bromine, products are tellurium tetrachloride, TeCL, a white, very hygroscopic crystalline solid, and tellurium tetrabromide, TeBr4, an orange crystalline solid ... 

Triethyl tellurium chloride,2 (CgHg TeCl, is isolated when an ether solution of tellurium tetrachloride is added dropwise to a similar solution of zinc diethyl. It crystallises from alcohol as colourless plates, M.pt. 174° C., readily soluble in alcohol, sparingly soluble in ether. It is deliquescent in air, and with moist silver oxide gives a hydroxide. 

In the series of the binary halides of selenium and tellurium, the crystal structure determinations of tellurium tetrafluoride (100) and of tellurium tetrachloride on twinned crystals (65, 66) were the key to understanding the various and partly contradictory spectroscopic and other macroscopic properties (e.g., 66,161,168,169,219,220, 412), as well as the synthetic potential of the compounds. In contrast to the monomeric molecular i//-tbp gas phase structures with C2v symmetry (417), the solid state structures of both are polynuclear. As the prototype of the chlorides and bromides of selenium and tellurium, crystalline tellurium(IV) chloride has a cubane-like tetrameric structure with approximate Td symmetry (Fig. 1). Within the distorted TeCla+a octa-hedra the bonds to the triply bridging chlorine ligands are much longer than to the terminal chlorines. The bonding system can be described either covalently as Te4Cli6 molecules, or, in an ionic approximation, as [(TeCl Cn4] with a certain degree of stereochemical activity of the lone pairs toward the center of the voluminous cubane center (65, 66). 

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