Polonium — radioactive chemical element VI of group of periodic Mendeleev's system, it treats chalcogens. Polonium represents soft silver-white metal. This element has no stable isotopes, but it is known 27 radioactive.
Instruction
1. Polonium was one of the first open radioactive elements, it was found by Pierre Curie and Maria Sklodowska-Curie in 1898. He received the name in honor of Poland — Maria Sklodowska-Curie's homeland. For the first time polonium was emitted from uranium pitch ore.
2. Polonium is a rare element, two of its crystal modifications are known: the low-temperature form with cubic a lattice, at a temperature above 36 °C is steady a form with a romboedrichesky lattice.
3. Polonium is present at small amounts in sea water, various marine organisms can accumulate it. This element gets into a human body together with food then it is evenly distributed on separate bodies.
4. In high concentrations polonium is extremely toxic, for work with it use special boxes. The toxicity of polonium was investigated in animal experiments, it caused changes of composition of peripheral blood and reduced life expectancy. At animals tumors of various bodies developed. Biological influence of polonium in small concentration is insufficiently studied.
5. On the chemical properties polonium is close to tellurium, in connections this element shows oxidation levels-2, +2, +4 and +6. Polonium is oxidized on air, it reacts with solutions of acids with formation of ions. In interaction with hydrogen this element gives flying hydride.
6. Heating metals with polonium vapors at a temperature of 400-1000 °C, receive polonida. Dioxide of polonium can exist in two crystal modifications: at a temperature below 54 °C the yellow form with a face-centered cubic lattice is stable, when heating dioxide passes into a red form with a tetragonal lattice. Monoxide of polonium represents solid substance of black color, it is formed at spontaneous decomposition of selenit or sulfite of polonium.
7. In gram quantities polonium is received by means of radiation of metal bismuth neutrons, process takes place in nuclear reactors. In microscopic quantities it can be allocated from waste of processing of uranium ores. It is received extraction, electrodeposition, sublimation and ionic exchange. Polonium is also formed at bismuth radiation by protons in a cyclotron.
8. Polonium is used as a power source in atomic batteries of spacecrafts and also in portable devices. It is applied to production of ampoule sources of neutrons.