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mesothorium

noun
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meso·​thorium | \ ¦me|zō, ¦mē|, |sō+ \

Definition of mesothorium

: either of two radioactive products intermediate between thorium and radiothorium in the thorium series or a mixture of the two products obtained usually from thorium minerals (as monazite sand) and used as a substitute for radium especially in luminous paints:
a : an isotope of radium

— called also mesothorium 1

—symbol MsTh1 or Ra228
b : an isotope of actinium

— called also mesothorium 2

—symbol MsTh2 or Ac228

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History and Etymology for mesothorium

New Latin, from mes- + thorium

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Cite this Entry

“Mesothorium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mesothorium. Accessed 21 Jun. 2021.

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