ionium

noun
io·ni·um | \ī-ˈō-nē-əm \

Definition of ionium 

: a natural radioactive isotope of thorium having a mass number of 230

First Known Use of ionium

1907, in the meaning defined above

History and Etymology for ionium

ion + -ium; so called from its ionizing action

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The first known use of ionium was in 1907

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More Definitions for ionium

ionium

noun
io·ni·um | \ī-ˈō-nē-əm \

Medical Definition of ionium 

: a natural radioactive isotope of thorium having a mass number of 230

More from Merriam-Webster on ionium

Britannica.com: Encyclopedia article about ionium

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