Radium is radioactive chemical element II of group of periodic Mendeleev's system, in a free look it represents silver-white metal which quickly grows dull on air. Radium belongs to alkaline-earth elements.
Instruction
1. Radium is very rare scattered element. Its main sources are uranium ores, 1 t of uranium contains about 0.34 g of radium. In very small concentration this chemical element was found in various objects, for example, in natural waters.
2. At radium the cubic body-centered crystal lattice, on an outer sheath of its atom is 2 electrons, for this reason at this element only one oxidation level +2. All compounds of radium have property of an autoluminescence, the pale blue luminescence in the dark is characteristic of them.
3. Many salts of radium are colourless, however, decaying under the influence of own radiation, they get brown or yellow coloring. Because of self-absorption of the particles which are let out at radioactive decay, radium constantly generates heat therefore temperature of its medicines is always a little higher than surrounding.
4. Metal radium quickly becomes covered on air by the film consisting of its oxide and nitride. It violently reacts with water, forming soluble hydroxide in water and emitting hydrogen. Bromide, nitrate, sulfide and chloride of radium are well dissolved in water. Chromate, a carbonate and oxalate — are badly soluble.
5. On the chemical properties this element is similar to barium, but is more active. Practically all compounds of radium are isomorphic to the corresponding compounds of barium. In comparison with other alkaline-earth metals, radium has weak tendency to complex formation. Its complexes with apple, wine, dairy and lemon acids are known.
6. Radium is emitted in the form of chloride and other salts as a by-product of processing of uranium ores. For this purpose apply methods of ionic exchange, fractional crystallization and sedimentation. By means of electrolysis on the mercury cathode receive metal radium.
7. Find this chemical element by radiometric methods. Radium is very toxic. In geology its isotopes apply to determination of age of minerals and sedimentary rocks. In geochemistry it is used as the indicator of circulation and shift of oceanic waters.
8. Long time radium was the only radioactive element which found the practical application in medicine, it was used for preparation of phosphors of a constant luminescence. However it was forced out by cheaper radionuclides received in the artificial way. Radium kept some value in medicine as a radon source for treatment by radonic bathtubs.