WebElements: Oxygen
- History, uses, occurrence, compounds, and properties. Features a picture of liquid oxygen and a sound file.
- http://www.webelements.com/webelements/elements/text/O/key.html

LANL: Oxygen
- Details of the history, sources, forms, compounds, and isotopes of oxygen.
- http://periodic.lanl.gov/elements/8.html

Visual Elements: Oxygen
- Explains the uses and physical properties of oxygen. Includes a visual representation and downloadable animation.
- http://www.chemsoc.org/viselements/pages/oxygen.html

ChemicalElements.com: Oxygen
- Features basic information, an atomic structure diagram, facts about oxygen and a table of isotopes.
- http://www.chemicalelements.com/elements/o.html

Wikipedia: Oxygen
- Article covering properties of the element, including its history, applications, and characteristics as well as safety precautions.
- http://en.wikipedia.org/wiki/Oxygen