Technetium(IV) oxide

Technetium dioxide was first produced in 1949 by electrolyzing a solution of ammonium pertechnetate under ammonium hydroxide and this method is used for separating technetium from molybdenum and rhenium. There are now more efficient ways of producing the compound, such as the reduction of ammonium pertechnetate by zinc metal and hydrochloric acid, stannous chloride, hydrazine, hydroxylamine, ascorbic acid, by the hydrolysis of potassium hexachlorotechnate or by the decomposition of ammonium pertechnetate at 700 °C under an inert atmosphere: ==Properties==

The dihydrate dehydrates to anhydrous technetium dioxide at 300 °C, and if further heated sublime at 1,100 °C under an inert atmosphere, however, if oxygen is present, it will react with the oxygen to produce technetium(VII) oxide at 450 °C. The solubility of technetium(IV) oxide is very low and is reported to be 3.9 μg/L. The main species when technetium dioxide is dissolved in water is TcO2+ at pH below 1.5, TcO(OH)+ pH between 1.5 and 2.5, TcO(OH)2 pH between 2.5 and 10.9, and TcO(OH) above pH 10.9. The solubility can be affected by adding various organic ligands such as humic acid and EDTA, or by the addition of hydrochloric acid. This can be a problem if technetium(IV) oxide is released into the soil, as it will increase the solubility. If technetium dioxide is electrolyzed in acidic conditions, the following reaction occurs: :TcO2·2H2O → TcO + 4 H+ + 3 e– The electrode potential measured for this reaction is kJ/mol. The molar magnetic susceptibility of TcO2·2H2O was found to be χm = . ==References==