Oxygen: meaning, definitions and examples

Used in general conversation or scientific contexts to refer to the chemical element essential for respiration and combustion.

• Plants produce oxygen during photosynthesis.
• We need oxygen to breathe.

Used in scientific notation to describe the diatomic molecule of oxygen, commonly in chemical equations, molecular biology, and other scientific fields.

• The balanced equation for the combustion of hydrogen is 2H2 + O2 → 2H2O.
• Oxygen exists primarily as O2 in the Earth's atmosphere.

Used in scientific and educational contexts to refer to oxygen in its pure, uncombined form. Often used to differentiate it from compounds containing oxygen.

• Elemental oxygen is a diatomic molecule at standard conditions.
• In chemical reactions, elemental oxygen can act as a powerful oxidizer.

Used in scientific and technical contexts to refer to single oxygen atoms, often in the study of atmospheric science or materials exposed to space environments.

• Atomic oxygen in low Earth orbit degrades satellite materials.
• The presence of atomic oxygen was detected in the upper atmosphere.