Английская Википедия:Americium(III) hydroxide
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Americium(III) hydroxide is a radioactive inorganic compound with the chemical formula Шаблон:Chem2. It consists of one americium atom and three hydroxy groups. It was first discovered in 1944, closely related to the Manhattan Project. However, these results were confidential and were only released to the public in 1945. It was the first isolated sample of an americium compound, and the first americium compound discovered.
Properties
Americium hydroxide is a pink solid[1] which is sparingly soluble in water.[2]
Due to self-irradiation, the crystal structure of Шаблон:Chem2 decomposes within 4 to 6 months (Шаблон:Chem2 has a half-life of 432.2 years); for Шаблон:Chem2 the same process takes one day (Шаблон:Chem2 has a half-life of 18.11 years).[1]
Synthesis
Americium metal can be converted to Шаблон:Chem2 in a four-step process. As described by the Oak Ridge National Laboratory, americium is added to hydrochloric acid, then neutralized using ammonium hydroxide (Шаблон:Chem2). A saturated oxalic acid solution is added to the now neutralized solution. This causes large americium oxalate crystals to begin to grow. Once complete precipitation is achieved, oxalic acid is once again added, to attain a slurry of americium oxalate and oxalic acid. The americium oxalate is then filtered out, washed with water, and is partially dried by allowing exposure to air.
The americium oxalate is then added to a platinum combustion boat to undergo calcination. The americium oxalate is dried in a furnace and will begin to decompose at 350 °C. When decomposition begins to occur, the oxalate will turn into the desired black americium dioxide. To ensure no oxalate remains in the americium dioxide, the oven temperature is increased to and held at 800 °C and then slowly allowed to cool to room temperature.
The americium dioxide is heated again, to about 600 °C, in the presence of hydrogen, to produce americium(III) oxide.
The final step involves the hydrolysis of the americium(III) oxide, to produce the final product, americium(III) hydroxide.[3]
Reactions
When ozone is bubbled through a slurry of americium(III) hydroxide in 0.03 M potassium bicarbonate at 92 °C, hexagonal Шаблон:Chem2 (potassium dioxoamericium(V) carbonate) can be obtained. Potassium carbonate can also be used. The resulting Шаблон:Chem2 reacts with dilute acids to produce americium dioxide.[4]
In a dilute base such as sodium hypochlorite, Шаблон:Chem2 gets oxidised to Шаблон:Chem2, which is black in solution. Further oxidation using ozone and sodium hydroxide can produce yellow hydroxy species of Am(VI).
See also
References
Шаблон:Americium compounds Шаблон:Hydroxides
