英语语法分析

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。

Even Francium's most stable isotope, Francium-223 only has a half-life of 22 minutes.

钫的最稳定的同位素，钫- 223也只有22分钟的半衰期。

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。