Assertion: hafnium | /r/HasProperty | predicted by dmitri mendeleev
Facets:
value: in 1869
type: TEMPORAL
Source sentences:
text: Hafnium had been predicted by Dmitri Mendeleev in 1869 and Henry Moseley measured in 1914 the effective nuclear charge by X-ray spectroscopy to be 72, placing it between the already known elements lutetium and tantalum.