ChemicalElements.com: Manganese
Basic information, atomic structure, and isotopes.
EnvironmentalChemistry.com: Manganese
Atomic structure, chemical and physical properties, and table of nuclides.
It's Elemental: Manganese
Basic physical and historical information.
Lenntech: Manganese
Physical data, chemical properties, health and environmental effects.
Manganese
Data tables and historic information.
Radiochemistry of Manganese
Full text of the monograph by R. P. Schuman (Dept. of Chemistry, Robert College, Bebek P.K.8, Istanbul, Turkey). [PDF]
USGS Minerals Information: Manganese
Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
Visual Elements: Manganese
General and physical information, source, uses, biological role, key isotopes, and ionisation energies.
WebElements: Manganese
Extensive information on history, uses, occurrence, compounds, and properties of the element.
Wikipedia: Manganese
Properties of the element, including its history, applications, and characteristics.