Basic information, atomic structure, and isotopes.
Atomic structure, chemical and physical properties, and table of nuclides.
Basic physical and historical information.
Physical data, chemical properties, and health effects.
Full text of the monograph by G. W. Leddicotte (Oak Ridge National Laboratory, Oak Ridge, Tennessee).
Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
Extensive information on history, uses, occurrence, compounds, and properties.
Properties of the element, including its history, applications, and characteristics.
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