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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 Ra228b : an isotope of actinium
— called also mesothorium 2
—symbol MsTh2 or Ac228Keep scrolling for more
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