Assertion: lanthanide contraction | /r/HasProperty | greater-than-expected decrease
Facets:
value: to 71, lutetium
type: OTHER
Source sentences:
text: The lanthanide contraction is the greater-than-expected decrease in ionic radii of the elements in the lanthanide series from atomic number 57, lanthanum, to 71, lutetium, which results in smaller than otherwise expected ionic radii for the subsequent elements starting with 72, hafnium.