Selenium trioxide complexes

Selenium trioxide shows the typical properties of a Lewis acid and forms 1 1 complexes with organic bases such as pyridine, y-picoline, quinoline, morpholine, and triethylamine in liquid SO2 or nitromethane. The complexes were found to be of donor-acceptor type, and IR spectroscopy suggests that selenium is coordinated via the nitrogen atom of the tertiary base. It has also been confirmed that the tetrameric ring of SeOs is retained in the adducts. 

Complex formation between arsenic or antimony(m) oxide and selenium trioxide gives the adducts M203,3Se03 but the corresponding pentoxides do... 

Ephraim and Muller 2 describe some results obtained with the groups — S04, — Se04, —Mo04, — W04, and —Cr04. These anions were united with the hexammino-nickel complex, and the temperature measured at which the ammonia tension is equal to atmospheric pressure. The stability of the complex is apparently independent of the atomic volumes of selenium, sulphur, chromium, molybdenum, and tungsten, but increases proportionally with the molecular volume of the corresponding trioxides. 

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. 

As previously noted, the high temperature of the combustion process causes the nitrogen and oxygen in the air to react to produce nitrogen oxides. The non-carbon (elements) impurities in the fuels react to form oxides sulfur dioxide is the primary hazardous product, but others such as selenium dioxide and arsenic trioxide are also produced. Mercury is released as vapor. When vented from the combustion zones this complex mixture of compounds blends with the air. Under the influence of sunlight, it continues to react to produce the complex product, smog. "... 

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