資料來源 : pyDict

新釷

資料來源 : Webster's Revised Unabridged Dictionary (1913)

Mesothorium \Mes`o*tho"ri*um\, n. [NL.; meso- + thorium.]
   (Chem.)
   A radioactive product intermediate between thorium and
   radiothorium, with a period of 5.5 years.