Advertisement
Advertisement
actinium
[ ak-tin-ee-uhm ]
noun
, Chemistry.
- a radioactive silver-white metallic element that glows blue in the dark, resembling the rare earths in chemical behavior and valence. : Ac; : 89; : 227.
actinium
/ ækˈtɪnɪəm /
noun
- a radioactive element of the actinide series, occurring as a decay product of uranium. It is used as an alpha-particle source and in neutron production. Symbol: Ac; atomic no: 89; half-life of most stable isotope, 227Ac: 21.6 years; relative density: 10.07; melting pt: 1051°C; boiling pt: 3200 ± 300°C
actinium
/ ăk-tĭn′ē-əm /
- A silvery-white, highly radioactive metallic element of the actinide series that is found in uranium ores. It is about 150 times more radioactive than radium and is used as a source of alpha rays and neutrons. Its most stable isotope has a half-life of about 22 years. Atomic number 89; melting point 1,050°C (1,922°F); boiling point (estimated) 3,200°C (5,792°F); specific gravity (calculated) 10.07; valence 3.
- See Periodic Table
Discover More
Word History and Origins
Origin of actinium1
C19: New Latin, from actino- + -ium
Discover More
Example Sentences
On Rutherford's theory then, actinium should always accompany uranium and radium, but in very subordinate amount.
From Project Gutenberg
For if actinium was an independent element we would be sure to find actinium haloes.
From Project Gutenberg
The element has since been found in nature as a small constituent of the natural decay of actinium.
From Project Gutenberg
The emanation deposits two successive disintegration products actinium-A and actinium-B.
From Project Gutenberg
What is the final non-active product of the series of changes we have traced from uranium through actinium and radium?
From Project Gutenberg
Advertisement
Advertisement
Advertisement
Advertisement
Browse