Assertion: lanthanoid contraction | /r/CapableOf | keep rare earth ions
Facets:
value: about the same size
type: OTHER
Source sentences:
text: Because the lanthanoid contraction keeps these rare earth ions about the same size and because they all generally exhibit the +3 oxidation state, their chemical properties are very similar, with the result that at least small amounts of each one are usually present in every rare earth mineral.