Basic information, atomic structure, and isotopes.

Atomic structure, chemical and physical properties, and table of nuclides.

Data tables and historic information.

Basic physical and historical information.

History, sources, uses, and properties.

Physical data, chemical properties, health and environmental effects.

Full text of the monograph by J. M. Nielsen (Hanford Laboratories, Hanford Atomic Products Operation, Richland, Washington). [PDF]

Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).

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

Extensive information on history, uses, occurrence, compounds, and properties of the element.

Properties of the element, including its history, applications, and characteristics.