Polonium (chemical symbol Po, atomic number 84) is one of the rarest elements known, and its content in the earth's crust is about 65438+ 1000 trillion, which is mainly obtained by artificial synthesis. Elemental substance is a silvery white metal that can glow in the dark. It was discovered by Madame Curie and her husband pierre curie in 1898.
In memory of Madame Curie's native Poland, they named this element polonium. Polonium is one of the most poisonous substances in the world. Polonium is a silvery white metal. Simple metal, similar in appearance to lead and soft in mass. This is an extremely rare radioactive metal. Soluble in concentrated sulfuric acid, nitric acid, dilute hydrochloric acid, aqua regia and dilute potassium hydroxide solution. All polonium isotopes are radioactive.
There are two kinds of isotope allotropes: α-Po is a single cube; β-Po is a single diamond. At about 36℃, the phase transition from α-Po to β-Po occurred. Physical properties are similar to thallium, lead and bismuth. Soluble in dilute nitric acid and dilute potassium hydroxide. Polonium is the rarest element (naturally occurring) in the world.
Isotope: There are three isotopes of polonium, all of which are radioactive. The most common and easily obtained polonium isotope is polonium -2 10, with a half-life of only 134 days, which is nearly 5000 times more radioactive than radium. Polonium -2 10 is very dangerous, so even a small amount of operation should be extra careful.
preparation method
Natural polonium exists in uranium ore and thorium ore. Because of its low content, polonium is mainly obtained by artificial synthesis. In pitchblende, polonium is obtained by the decay of bismuth. It can be prepared by reducing polonium chloride with zinc.
Gram of polonium can be produced by neutron irradiation and bismuth decay, and the preparation of a large amount of polonium depends on large equipment such as nuclear reactors, but it is usually made in nuclear reactors or particle accelerators under the strict supervision of international agreements, and the global annual output is only about100g.