oxygen: Quick Facts

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Nov. 7, 2026

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Scientists accidentally solve a chemistry mystery that lasted 60 years • Nov. 6, 2026, 4:30 PM ET (Science Daily)

Scientists smash oxygen nuclei to recreate matter from the Big Bang • Oct. 30, 2026, 10:11 PM ET (Science Daily)

Facts

Also Known As	O

Photos and Videos

A labeled diagram of the periodic table entry for oxygen, showing its atomic number 8, symbol O, electron configuration, atomic weight range, orthorhombic crystal structure, and its classification as a nonmetal gas at room temperature.

explosion limits

A scientific graph shows the estimated abundance of oxygen in Earth's atmosphere over time on a logarithmic scale, with key evolutionary and geological events such as the first appearance of oxygenic photosynthesis, the rise of land plants, and the emergence of animals labeled along the curve.

Diagram illustrating the oxygen cycle, showing how atmospheric oxygen and carbon dioxide move between the atmosphere, plants, animals, water, and soil through processes like photosynthesis, respiration, combustion, and precipitation. Blue arrows represent the water cycle, while red and black arrows trace oxygen and carbon dioxide exchanges in the environment.

Diagram illustrating ozone chemistry in pure oxygen, showing the cyclical reactions between molecular oxygen (O2), atomic oxygen (O), and ozone (O3), with arrows indicating conversion steps and the role of light energy.

Diagram showing the formation of a polar covalent bond in a water molecule, with two hydrogen atoms bonding to one oxygen atom to form H2O, illustrating shared electrons and chemical reaction.

A vertical temperature scale shows the cryogenic region, highlighted from absolute zero up to about 90 kelvin, with key points where gases like oxygen, nitrogen, hydrogen, and helium liquefy, alongside temperature conversions between kelvin, Celsius, Fahrenheit, and Rankine.

Figure 1: Schematic diagram of a zirconia oxygen sensor used to monitor automobile exhaust gases. The sensor, approximately the size of a spark plug, is fitted into the exhaust manifold of an automobile engine. The thimble-shaped zirconia sensor, sandwiched between thin layers of porous platinum, is exposed on its interior to outside air and on its exterior to exhaust gas passing through slits in the sensor shield. The two platinum surfaces serve as electrodes, conducting a voltage across the zirconia that varies according to the difference in oxygen content between the exhaust gas and the outside air.

A swimmer wearing goggles and a swim cap turns their head to breathe while swimming in open water, emphasizing the act of breathing during exercise.

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Topics

oxygen-18 oxygen-16 liquid oxygen oxygen-17 ozone oxygen oasis hypoxia nitric acid air Oxygen cycle hydrogen carbon sodium nitrogen sulfur phosphorus boron iodine fluorine noble gas

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Key People

Carl von Linde

Carl von Linde

German engineer

Portrait of French chemist Antoine Laurent Lavoisier, shown in formal 18th-century attire with a white wig and ruffled cravat, looking slightly to his left.

Antoine Lavoisier

French chemist

Joseph Priestley

Joseph Priestley

English clergyman and scientist

German Swedish chemist Carl Wilhelm Scheele, c. 1780.

Carl Wilhelm Scheele

Swedish chemist

Mayow, detail of an engraving

John Mayow

English chemist and physiologist

Periodic Table of the elements concept image (chemistry)

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Concept artwork on the periodic table of elements.

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