Meaning & use
unununium
Last updated
The former temporary systematic name for the chemical element with atomic number 111, now officially called roentgenium.
See it in a sentence
Textbooks from the 1990s still refer to element 111 by its placeholder name, unununium.
Unununium was renamed roentgenium in 2004 to honor the discoverer of X-rays.
A note on using this word
Built from Latin numeral roots (un-un-un-, i.e., 1-1-1) under IUPAC's systematic element-naming convention used before a permanent name is assigned.
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