Assertion: cerium's use | /r/Desires | extreme conditions
Facets:
value: normally
type: DEGREE
Source sentences:
text: Its 59 electrons are arranged in the configuration [Xe]4f36s2; theoretically, all five outer electrons can act as valence electrons, but the use of all five requires extreme conditions and normally, praseodymium only gives up three or sometimes four electrons in its compounds.