11. In 1939, Perey discovered the element francium by purifying samples of lanthanum that contained actinium. 12. Of elements whose most stable isotopes have been identified with certainty, francium is the most unstable. 13. So even the " meaning " of a melting point for francium is a bit obscure. 14. I don't think you need a citation for saying that francium salts are expected to be soluble. 15. Francium does not exist for long enough to be able to react with water due to its extreme instability.16. Francium -221 then decays into astatine-217 by alpha decay ( 6.457 MeV decay energy ).17. Francium 's ability to be synthesized, trapped, and cooled, along with its relatively simple quantum theory.18. "' Francium "'is a chemical element that has the symbol Fr and atomic number 87. 19. All other previous purported discoveries of element 87 were ruled out due to francium 's very limited half-life. 20. An example is the separation of francium from other radioactive elements by coprecipitating it with caesium salts such as caesium perchlorate.
