a radioactive element of the alkali-metal group discovered as a disintegration product of actinium
例句
The half-life of francium is 22 minutes. 钫的半衰期是22分钟。
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。
So little is known about it, because there is only about 1 ATOM OF FRANCIUM IN A CUBIC FOOT OF URANIUM ORE! 对它所知甚少,因为在1立方英尺的铀矿石中,仅有1个钫原子!
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。
The half-life of francium is 22 minutes 钫的半衰期是22分钟。
