Assertion: neptunium | /r/AtLocation | nature
Facets:
value: in negligible amounts
type: OTHER
Source sentences:
text: Thus neptunium is present in nature only in negligible amounts produced as intermediate decay products of other isotopes.
text: Neptunium can be found in the nature only in ultratraces resulting from nuclear weapons experiments, radioactive wastes from nuclear reactors or from other experiments.
text: It used to be very rare and for a long time, people thought that neptunium didn’t exist in nature and was a man-made element, but we now know that very small amounts can be found in the Earth’s crust.
text: However, as neptunium does in fact occur in nature in trace amounts, as demonstrated when it was found in uranium ore in 1952, it is possible that Hulubei and Cauchois did in fact observe neptunium.
text: All the elements with higher atomic numbers have been first discovered in the laboratory, with neptunium and plutonium later also discovered in nature.
text: Thus neptunium is present in nature only in negligible amounts produced as intermediate decay products of other isotopes.
text: Also neptunium can be found in the nature only in ultratraces resulting from nuclear weapons experiments or other experiments.