francium

noun

1. 钫（放射性化学元素）
   a chemical element. Francium is a radioactive metal.

1. Francium is the densest of the Alkali Metals and also radioactive.
   钫是碱金属中密度最大的，具有放射性。
2. The half-life of francium is 22 minutes.
   钫的半衰期是22分钟。
3. Any of the monovalent metals of group I of the periodic table ( lithium or sodium or potassium or rubidium or cesium or francium).
   周期表中I族的任何单价金属（锂、钠、钾、铷、铯和钫）。
4. Even Francium's most stable isotope, Francium-223 only has a half-life of22 minutes.
   钫的最稳定的同位素，钫-223也只有22分钟的半衰期。
5. Because Francium is mainly only found synthetically in laboratory research, it has no known use outside of the laboratory.
   由于钫主要仅在实验室研究中产生，它在实验室外没有已知的用途。

noun

1. a radioactive element of the alkali-metal group discovered as a disintegration product of actinium

   Synonym:    Fratomic number 87