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Francium-223 is the most stable isotope, with a half-life of 21.8 minutes, [8] and it is highly unlikely that an isotope of francium with a longer half-life will ever be discovered or synthesized. [22] Francium-223 is a fifth product of the uranium-235 decay series as a daughter isotope of actinium-227; thorium-227 is the more common daughter. [23]
Perey named the element francium, after her home country, and it joined the other alkali metals in Group 1 of the periodic table of elements. [3] [7] Francium is the second rarest element (after astatine) — only about 550g exists in the entire Earth's crust at any given time — and it was the last element to be discovered in nature.
Francium compounds are compounds containing the element francium (Fr). Due to francium being very unstable, its salts are only known to a small extent. Francium coprecipitates with several caesium salts, such as caesium perchlorate, which results in small amounts of francium perchlorate.
Briefly, co-precipitation happens in this case due to the similar sizes of the caesium and francium cations. What happens is that when you have a solution with Cs+, Fr+, and ClO4- and you obtain crystals, they will have a mixed structure (basicaly CsClO4 with some Cs+ sites replaced by Fr+).
Francium, formerly known as eka-caesium and actinium K, is a chemical element that has the symbol Fr and atomic number 87. It has the lowest known electronegativity and is the second rarest naturally occurring element (after Astatine). Francium is a highly radioactive metal that decays into astatine, radium, and radon.
As a result, element 173 is expected to behave chemically like an alkali metal, and one that might be far more reactive than even caesium (francium and element 119 being less reactive than caesium due to relativistic effects): [90] [19] the calculated ionisation energy for element 173 is 3.070 eV, [91] compared to the experimentally known 3.894 ...
At last count 96/97 of the 97 elements (hydrogen through einsteinium, except astatine and francium) isolated in pure form and in macroscopic quantities have images. There are few images of very low encyclopedic quality for which it should be relatively easy to obtain higher quality: Ca. One element is still missing an image: Rn.
Francium compounds This page was last edited on 23 October 2017, at 22:31 (UTC). Text is available under the Creative Commons Attribution-ShareAlike 4.0 ...