Assertion: metal's point | /r/HasProperty | uncertain
Facets:
value: because of radioactivity
type: CAUSE
value: because of the element's extreme rarity
type: CAUSE
Source sentences:
text: The melting point is uncertain because of the element's extreme rarity and radioactivity; a different extrapolation based on Dmitri Mendeleev's method gave 20±1.5 °C (