Tellurium Nitrate

Basic tellurium nitrate, Te02, is made by dissolving Te in HN03. Thermal decomposition begins at 190°C and is complete at 300°C. 

Another group of methods involves the conversion of the tellurium into some compound, inorganic or organic, which can be purified and then made to regenerate the element. Hydrogen telluride,7 crystalline telluric acid,8 basic tellurium nitrate 9 and diphenyl telluride 10 have all been made use of. 

The oxidation can also be effected in the wet way, for example by the gradual addition of finely divided tellurium (preferably precipitated) to excess of nitric acid. A basic tellurium nitrate is the primary product (see later, p. 390), but on suitably diluting with water, tellurium dioxide is obtained as a colourless, crystalline precipitate.4 An... 

Basic Tellurium Nitrate, Te203(0H)N03, which has already been mentioned (p. 379), is formed when a solution of tellurium or tellurium dioxide in nitric acid is evaporated without excessive heating.6 It crystallises in rhombic pyramidal crystals (a b c=0-590 1 0-607).7... 

Tellurium and Nitrogen —Tellurium Nitride, Tellurium Nitrite, Basie Tellurium Nitrate. 

Basic tellurium nitrate or sulphate. Concentrated nitric or sulphuric add. 

Only a few examples of this class of compounds containing divalent tellurium are known. The aryl tellurium nitrates and perchlorates have been isolated only in the form of their adducts with thiourea, triphenylarsine oxide, or as hetaryl A -oxidcs. 

Phenyl thiourea tellurium nitrate and perchlorate were isolated when nitric or perchloric acid were added to aqeuous solutions containing phenyl tellurium chloride and thiourea. 

C4HsCd04 Noncombustible solid. The solution is basic reacts with acids, producing heat. Incompatible with strong oxidizers, elemental sulfur, selenium, sulfides, tellurium, nitrates. In the heat of fire, toxic cadmium oxide fumes may form. CADMIUM BROMIDE (7789-42-6) CdBrj Noncombustible solid. Hydrolyzes in water, forming cadmium and bromic acid. Reacts with sulfides. Aqueous solution is inconqiatible with potassium. Incompatible with sulhiric acid, alkalis, ammonia, aliphatic amines, alkanolamines, alkylene oxides, amides, epichlorohydrin, organic anhydrides, isocyanates, nitromethane, vinyl acetate. 

Commercial Mg of at least 99.8% purity is used the tellurium must be purified in most cases because of its selenium content. Twice recrystallized basic tellurium nitrate is freed of nitric acid by boiling in concentrated HgSO, and then HCl gas is passed through the boiling solution for several hours. Finally, the solution is diluted and the Te is precipitated with hydrazine. The Te, stiU containing some oxide, is distilled imder vacuum. 

Sixty-five milliliters of concentrated nitric acid is then added and the solution boiled until oxides of nitrogen have been expelled. Basic nitrates of antimony and bismuth precipitate at this point if these substances are present as impurities. These are removed by filtering through asbestos, after which the clear liquor is evaporated gently on a water bath under a hood in an open 600-ml. beaker. Basic tellurium nitrate is deposited. The evaporation is continued until the solution volume has been reduced to 100 ml. The solution is then cooled. The crystalline deposit is filtered, washed with water on a suction filter, and air-dried. 

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