Assertion: actinium's electron | /r/HasProperty | involved
Facets:
Source sentences:
text: Karl Gschneidner, analysing the melting points of the lanthanides in a 1971 article, reached the conclusion that it was likely that 4f, 5d, 6s, and 6p electrons were all involved in the bonding of lanthanide metals except for lutetium, where 4f electrons were not found to be involved.