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| Occurrence and Production of Francium |
 Natural Occurrence
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| Francium-223 is the result of the alpha decay of actinium-227 and can be found in trace amounts in uranium and thorium minerals. In a given sample of uranium, there is estimated to be only one francium atom for every 1018 uranium atoms. It is also calculated that there is at most 30 g of francium in the Earth's crust at any time. This makes it the second rarest element in the crust after astatine. |
| Synthesis
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| Francium can be synthesized in the nuclear reaction; |
197Au + 18O  210Fr + 5n
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| This process, developed by Stony Brook Physics, yields francium isotopes with masses of 209, 210, and 211, which are then isolated by the Magneto Optic Trap (MOT). Other synthesis methods include bombarding radium with neutrons, and bombarding thorium with protons, deuterons, or helium ions. No weighable amount of francium has been synthesized. |