Tellurium halide complexes

Other tellurium complex halides. Tellurium forms a number of complex halides in the II as well as the IV state, some of the best-known being those with thiourea (tu) or substituted thioureas as ligands. The red Telv compounds are made by treating Te02 in concentrated hydrochloric acid solution with, e.g., tetramethylthiourea (Me4tu) ... 

Intermolecular Interactions in Tellurium(II) Halide Complexes with S or Se Donors 856... 

In addition to complex halides and cyanides, the metals form many ammines. Organic compounds of nitrogen, arsenic, sulphur, selenium and tellurium arc other possible ligands. Many complexes with bidentate ligands are known. The various types of isomerism are common thus Pd(NH3)2Cl2 occurs as the pink [Pd (NH3)4] [PdCy and as the yellow cis and trans isomers ... 

Pseudohalides of Se in which the role of halogen is played by cyanide, thiocyanate or selenocyanate are known and, in the case of Se are much more stable with respect to disproportionation than are the halides themselves. Examples are Se(CN)2, Se2(CN)2, Se(SeCN)2, Se(SCN)2, Se2(SCN)2. The selenocyanate ion SeCN is ambidentate like the thiocyanate ion, etc., p. 325), being capable of ligating to metal centres via either N or Se, as in the osmium(IV) complexes [OsCl5(NCSe)], [OsCl5(SeCN)], and trans-[OsCU(NCSe)(SeCN)]2-.920) Tellurium and polonium pseudohalogen analogues include Te(CN)2 and Po(CN)4 but have been much... 

The basic salts of quadrivalent polonium, such as the sulfate and sele-nate, show a marked resemblance to those of tellurium and further resemblances appear in the quadrivalent halides, particularly in their complexing with halide ions in solution, while complexing of polonium(IV) with weak acids, such as acetic, oxalic and tartaric, seems to be more marked than is the case with tellurium. 

Tellurium Halides. Tellurium forms the dihalides TeCl and TeBi, but not Tel2. However, it forms tetrahalides with all four halogens. Tellurium decafluoride [53214-07-6] and hexafluoride can also be prepared. No monohalide, Te2X2, is believed to exist. Tellurium does not form well-defined oxyhalides as do sulfur and selenium. The tellurium halides show varying tendencies to form complexes and addition compounds with nitrogen compounds such as ammonia, pyridine, simple and substituted thioureas and anilines, and ethylenediamine, as well as sulfur trioxide and the chlorides of other elements. 

Tellurium pseudohalides, such as the dicyanide [14453-24-8] Te(CN)2, the dithiocyanate [83543-04-8] Te(SCN)2, and thiourea complexes with Te(SCN)2, have been prepared. These are similar to the halides in properties. 

Oxidation of ethylene to ethylene glycol and its mono- and diacetates has also been catalyzed by tellurium and thallium complexes in the presence of halides... 

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