Tellurium salt

In many reactions, selenium is an oxidant as well as a reductant. Strong oxidants convert selenium dioxide and its derivatives to the hexavalent state. Although hexavalent selenium compounds are oxidants, these are less active and difficult to reduce. Selenium salts resemble the corresponding sulfur and tellurium salts in behavior. 

Tellurium dioxide is used to prepare tellurium metal, telluric acid, and many tellurium salts. 

Indications of poisoning by tellurium salts are an odour of garlic of the exhaled air, a headache, accelerated breathing and pulse, a feeling of fatigue and dizziness. 

Tellurium Dioxide as an Acid Anhydride.—When tellurium tetrachloride is treated with water, or when an aqueous solution of a tellurium salt is decomposed by an aqueous alkaline solution, a bulky, colourless precipitate is obtained which is sufficiently soluble in water to impart an acid reaction to the solution and which is more readily soluble than tellurium dioxide in acids or alkalis. A similar precipitate is obtained on acidifying a cold aqueous solution of potassium tellurite with a slight excess of nitric acid. This product is a tellurous acid, possibly H2TeOs, but it is very unstable and spontaneously dehydrates, slowly at the ordinary temperature and rapidly at 40° C. with formation of dioxide.1... 

For extinction coefficients and molecular conductivities of Vernon s isomeric a-and -dimethyl tellurium salts, see Lowry, Goldstein and Gilbert, J. Chem. Soc., 1928, p. 307. 

For organic synthesis applications, C-C bond formation between the R group and an alkene carbon atom is of paramount importance and Pd-catalyzed R-R coupling is to be avoided. Equation (5) displays a palladium-catalyzed Mizorki-Heck-type (MH) reaction using tellurium salts. ... 

SYNS DIETHYLDITHIOCARBAMIC ACID TELLURIUM SALT NCI-C02857 TELLURIUM DIETHYLDI-THIOCARBAMATE TETRAKIS(DIETHYLCARBAMO-... 

Just as sulfur ylids react with the carbonyl of an aldehyde or ketone to give an epoxide, tellurium ylids react with imines to give an aziridine. The reaction of an aUyhc tellurium salt, RCH=CHCH2Te Bu2 Br, with lithium hexamethyldisila-zide in HMPA/toluene leads to the tellurium yhd via deprotonation. In the presence of an imine, the ylid add to the imine and subsequent displacement of Bu2Te generates an aziridine with a pendant vinyl group. ... 

Organic acids like tartaric and citric dissolve tellurium oxide, forming acid salts, Te(HC4Hi06)< and Te(HC H9C>7)2.4 Oxalic, lactic, malic, and gallic acids dissolve appreciable amounts of tellurium dioxide, but the tellurium salts of these acids have not been isolated. Succinic acid does not dissolve Te02, and the existence of tellurium oleate and stearate is doubtful. 

The black modification of selenium ( selenium nigrum ) reacts much less smoothly. Black tellurium powder reacts very slowly a possible explanation for this inert behaviour is that this Te, obtained by precipitation from solutions of tellurium salts, is readily inactivated by formation of oxide on the particles. 

Akrochem TDEC Carbamodithioic acid, diethyl-, tetrakis(anhydrosulfide) with thiotelluric acid CCRIS 304 Diethyidithio carbamic acid tellurium salt EINECS 244-121-9 Ethyl tellurac HSDB 4123 NCI-C02857 Nocceler TTTE Perkacit TDEC Tellurac Tellurium bis(diethyldithiocarbamate) Tellurium diethyidithiocarb-amale Tellurium, tetrakis(diethylcarbamodithioato-... 

Tellurium excretion patterns depend on the chemical forms and mode of administration of the compounds. Parenterally administered tellurium is excreted mainly in the urine rather than the feces, whereas orally ingested tellurium salts are excreted mainly in the feces (Durbin 1960). After oral dosing to rats, 60 -80% of ingested tellurite is rapidly excreted in the feces. The absorbed tellurium is secreted in the bile and enters the intestine. Small amounts of absorbed elemental tellurium and tellurite are exhaled ( 0.1%) presumably as dime-thyltelluride, and produce a characteristic garlic-like breath odor (De Meio 1946). 

Although tellurium in elemental form has low toxicity, ingestion can produce nausea, vomiting, tremors, convulsions, and central nervous system depression. In addition, exposure to the metal or to its compounds can generate garlic-like odor in breath, sweat, and urine. Such odor is imparted by dimethyl telluride that is formed in the body. Oral intake of large doses of the metal or its compounds can be lethal. Clinical symptoms are similar for most tellurium salts, which include headache, drowsiness, loss of appetite, nausea, tremors, and convulsions. High exposure can produce metallic taste, dry throat, chill and other symptoms. Inhalation of dust or fume of the metal can cause irritation of the respiratory tract. Chronic exposure can produce bronchitis and pneumonia. 

TeDEC is produced from diethylamine, carbon disulfide, and a tellurium salt as shown in Figure 10.46. 

Other evidence of the dependence of 5 E) upon the electron withdrawing ability of substituents comes from work on tellurium salts and the species R2TeX2, and the substantial increase in resonance frequency that occurs when R2E forms a metal complex by lone pair donation. " In addition, estimates of charge densities at selenium based on CNDO calculations in IX, X and other heterocycles support this... 

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