ionium

[ahy-oh-nee-uh m]
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noun Chemistry.

a naturally occurring radioactive isotope of thorium. Symbol: Io; atomic number: 90; atomic weight: 230.

Nearby words

  1. ionian islands,
  2. ionian mode,
  3. ionian sea,
  4. ionic,
  5. ionic bond,
  6. ionization,
  7. ionization chamber,
  8. ionization or ionizing,
  9. ionization potential,
  10. ionize

Origin of ionium

First recorded in 1905–10; ion + -ium

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for ionium

  • Ionium expels an alpha particle and becomes radium, which is a bivalent element resembling barium belonging to the second group.

    A Brief Account of Radio-activity|Francis Preston Venable


British Dictionary definitions for ionium

ionium

noun

obsolete a naturally occurring radioisotope of thorium with a mass number of 230Symbol: Io

Word Origin for ionium

C20: from New Latin, from ion + -ium

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012