Frances discovered researcher Margarita Perey in 1939, she called her open a new element in honor of his homeland.The existence of this element and its basic properties have been predicted in 1870 by Mendeleev, but all attempts to find it in nature ended in failure.Only in 1939 it succeeded in isolating French researcher.
27 known radioactive isotopes with mass numbers of France, lying in the range from 203 to 229. At present there is an element of stable and long-lived isotopes.In this regard, all of the studies carried out with its properties of tracer amounts of substance.In nature, francium present in trace amounts.Because of the very high rate of radioactive decay properties of the metal can be learned only for samples which contain trace amounts of this element.
In the compounds of France was one oxidat
ion state and in solution behaves like a typical alkali metal in their chemical properties, it is more reminiscent of cesium.France - the most fusible metal after mercury.At room temperature it is a liquid and resembles a mercury.
good solubility in water the following compounds France nitrate, chloride, sulfate, fluoride, acetate, carbonate, sulfide, oxalate and hydroxide.Poorly soluble - iodate, chloroplatinate, hloroantimonat, chlorine-rostannat, nitrokobaltat and hlorovismutat.
France isotopes with mass number greater than 215, are formed by the splitting of uranium and thorium under irradiation with accelerated protons and deuterons.Isotopes with mass number less than 213 can be obtained by nuclear reactions of multiply charged ions with different elements.
France could be separated by chromatography on organic and inorganic sorbents, co-precipitation, electrophoresis and extraction.During crystallization precipitated it is isomorphic with perchlorate salts and cesium hexachloroplatinate.
coprecipitated France with a double and simple cesium salts, and salts of heteropolyacids, such as salts or silicotungstic acids vanadievofosfornovolframovoy.Extract with its nitrobenzene in the presence of sodium tetraphenylborate.Branch rubidium and cesium carried by paper chromatography using cation exchange resins and inorganic sorbents.
France uses in biological research for the study of migration of heavy alkali metals, as well as in medicine, for example, for the diagnosis of cancer.