Especiál Gas Inc.: Argon - Numeric data, uses, and general information. It's Elemental: Argon - Basic physical and historical information. ChemicalElements.com: Argon - Basic information, atomic structure, and table of isotopes. EnvironmentalChemistry.com: Argon - Atomic structure, chemical and physical properties, and table of nuclides. Lenntech: Argon - Physical data, chemical properties, health and environmental effects. Wikipedia: Argon - Details the properties of the element, including its history, applications, and characteristics. WebElements: Argon - Extensive information on history, uses, occurrence, and properties of the element.