ChemicalElements.com: Magnesium
Basic information, atomic structure, and table of isotopes.
EnvironmentalChemistry.com: Magnesium
Atomic structure, chemical and physical properties, and table of nuclides.
It's Elemental: Magnesium
Basic physical and historical information.
LANL: Magnesium
History, properties, uses, compounds, and handling.
Lenntech: Magnesium
Physical data, chemical properties, health and environmental effects.
Magnesium
Data tables and historic information.
Radiochemistry of Magnesium
Full text of the monograph by A. W. Fairhall (Dept. of Chemistry, University of Washington, Seattle, Washington). [PDF]
USGS Minerals Information: Magnesium
Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
Visual Elements: Magnesium
Image, general and physical information, source, uses, key isotopes, and ionisation energies.
WebElements: Magnesium
Extensive information on history, uses, occurrence, compounds, and properties of the element.
Wikipedia: Magnesium
Properties of the element, including its history, applications, and characteristics.