Assertion: protactinium | /r/HasProperty | natural chemical element
Facets:
Source sentences:
text: Protactinium is a natural chemical element, found in uranium ores as pitchblende in extremely low concentrations; but protactinium can be obtained artificially by nuclear reactions from 232Th.
text: Protactinium is a natural chemical element, found in uranium ores as pitchblende in extremely low concentrations; but protactinium can be obtained artificially by nuclear reactions from 232Th.
text: Protactinium is a natural chemical element; protactinium can be separated from uranium ores.