Data tables and historic information.

Basic information, atomic structure, and table of isotopes.

Atomic structure, properties, and table of nuclides.

Basic physical and historical information.

History, sources, properties, and uses.

Physical data, chemical properties, health and environmental effects.

Full text of the monograph by William J. Maeck (Phillips Petroleum Company, Atomic Energy Division, Idaho Falls, Idaho). [PDF]

Overview and a number of publications in PDF format.

Image, source, uses, general and physical information, and key isotopes.

Extensive information on history, uses, occurrence, compounds, and properties.

Details the properties of the element, including its history, applications, and characteristics.