Answer: ionium

AnswerCrossword Clue
IONIUMThorium isotope
IONIUMRadioactive element discovered in 1907.
IONIUMRadioactive isotope having mass 230
IONIUMRadioactive isotope
IONIUMThorium-230, alternatively
IONIUMIsotope of thorium
ioniuman isotope of thorium
ioniumnaturally occurring radioactive isotope of thorium. Symbol: Io; at. no.: 90; at. wt.: 230