ChemGlobe: Manganese
Electronic, thermal, and steric data along with an isotope table.
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.
LANL: Manganese
Sources, properties, uses, and handling.
Lenntech: Manganese
Physical data, chemical properties, health and environmental effects.
Manganese and Compounds
An 8 page monograph
Radiochemistry of Manganese
Full text of the monograph by R. P. Schuman (Dept. of Chemistry, Robert College, Bebek P.K.8, Istanbul, Turkey). [PDF] (July, 1971)
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.