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The CsFr molecule is predicted to have francium at the negative end of the dipole, unlike all known heterodiatomic alkali metal molecules. Francium superoxide (FrO 2) is expected to have a more covalent character than its lighter congeners; this is attributed to the 6p electrons in francium being more involved in the francium–oxygen bonding. [4]
Francium-223 also has a shorter half-life than the longest-lived isotope of each synthetic element up to and including element 105, dubnium. [8] Francium is an alkali metal whose chemical properties mostly resemble those of caesium. [8] A heavy element with a single valence electron, [9] it has the highest equivalent weight of any element. [8]
Francium chloride is a radioactive chemical compound with the formula FrCl. It is a salt predicted to be a white solid and is soluble in water.
The most reactive metals, such as sodium, will react with cold water to produce hydrogen and the metal hydroxide: 2 Na (s) + 2 H 2 O (l) →2 NaOH (aq) + H 2 (g) Metals in the middle of the reactivity series, such as iron , will react with acids such as sulfuric acid (but not water at normal temperatures) to give hydrogen and a metal salt ...
However, it would appear that francium perchlorate has been formed, as it coprecipitates with caesium perchlorate, and several other insoluble francium salts are similarly known (Hyde, E.K., Radiochemical Methods for the Isolation of Element 87 (Francium), J. Am. Chem. Soc., 1952, 74, 4181) The article also quotes a value for the Pauling ...
Why is francium so unstable? The article doesn't explain. Google found me a Prezi presentation ( [1] ), but first off that's not a reliable source for expanding the francium article, and secondly it doesn't explain why many isotopes of related elements, e.g. 238 U with 54 more neutrons than protons, are so much longer lived.
Water-reactive substances [1] are those that spontaneously undergo a chemical reaction with water, often noted as generating flammable gas. [2] Some are highly reducing in nature. [ 3 ] Notable examples include alkali metals , lithium through caesium , and alkaline earth metals , magnesium through barium .
This is especially problematic for francium, which by relativistic calculations can be shown to be less electronegative than caesium, but for which the only value (0.7) in the literature predates these calculations.