Assertion: hafnium's isotope | /r/HasProperty | observed
Facets:
Source sentences:
text: At least 34 isotopes of hafnium have been observed, ranging in mass number from 153 to 186.
text: Out of isotopes whose half-lives are known, the lighter isotopes usually have shorter half-lives; half-lives of under 50 μs for 253Rf and 254Rf were observed.