Share this entry

Share this page

protactinium

Syllabification: prot·ac·tin·i·um
Pronunciation: /ˌprōˌtakˈtēnēəm
 
/

Definition of protactinium in English:

noun

The chemical element of atomic number 91, a radioactive metal of the actinide series, occurring in small amounts as a product of the natural decay of uranium. (Symbol: Pa)
Example sentences
  • Along the way, these disintegration series produce radioactive isotopes of protactinium, thorium, actinium, radium, francium, radon, astatine, polonium, bismuth, lead, thallium and mercury.
  • A new method of radioactive tracing involves the use of a new clock, based on the radioactive decay of uranium - 235 to protactinium - 231.
  • The dates of discovery of these elements as 1789 for uranium, 1829 for thorium, 1899 for actinium and 1913 for protactinium.

Origin

early 20th century: from proto- 'original, earlier' + actinium, so named because one of its isotopes decays to form actinium.

Definition of protactinium in:

Share this entry

Share this page

 

What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.

Get more from Oxford Dictionaries

Subscribe to remove ads and access premium resources

Word of the day terpsichorean
Pronunciation: ˌtərpsikəˈrēən
adjective
of or relating to dancing