Oxygen (O)
nonmetalGas
Standard Atomic Weight
15.999 u [15.99903, 15.99977]Electron configuration
[He] 2s2 2p4Melting point
-218.79 °CBoiling point
-182.95 °CDensity
1.429 kg/m³Oxidation states
−2, −1, 0, +1, +2Electronegativity (Pauling)
3.44Ionization energy (1st)
13.618055 eVDiscovery year
1771Atomic radius
60 pmDetails
Oxygen is a reactive nonmetal and chalcogen that occurs mainly as the diatomic gas O₂ and, less commonly, as ozone O₃. It is essential to aerobic respiration and is a major constituent of water, silicate minerals, carbonates, and many biological molecules. Its high electronegativity and ability to form strong bonds make oxidation chemistry central to combustion, corrosion, metabolism, and industrial processing.
The gas is colorless, odorless, and tasteless. The liquid and solid forms are a pale blue color and are strongly paramagnetic.
The name derives from the Greek oxys for "acid" and genes for "forming" because the French chemist Antoine-Laurent Lavoisier once thought that oxygen was integral to all acids.
Oxygen was discovered independently by the Swedish pharmacist and chemist Carl-Wilhelm Scheele in 1771, and the English clergyman and chemist Joseph Priestley in 1774. Scheele's Chemical Treatise on Air and Fire was delayed in publication until 1777, so Priestley is credited with the discovery because he published first.
Oxygen had been produced by several chemists prior to its discovery in 1774, but they failed to recognize it as a distinct element. Joseph Priestley and Carl Wilhelm Scheele both independently discovered oxygen, but Priestly is usually given credit for the discovery. They were both able to produce oxygen by heating mercuric oxide (HgO). Priestley called the gas produced in his experiments 'dephlogisticated air' and Scheele called his 'fire air'. The name oxygen was created by Antoine Lavoisier who incorrectly believed that oxygen was necessary to form all acids. Oxygen is the third most abundant element in the universe and makes up nearly 21% of the earth's atmosphere. Oxygen accounts for nearly half of the mass of the earth's crust, two thirds of the mass of the human body and nine tenths of the mass of water. Large amounts of oxygen can be extracted from liquefied air through a process known as fractional distillation. Oxygen can also be produced through the electrolysis of water or by heating potassium chlorate (KClO3).
From the Greek word oxys, acid, and genes, forming. The behavior of oxygen and nitrogen as components of air led to the advancement of the phlogiston theory of combustion, which captured the minds of chemists for a century.
Joseph Priestley is generally credited with its discovery, although Scheele also discovered it independently.
Its atomic weight was used as a standard of comparison for each of the other elements until 1961 when the International Union of Pure and Applied Chemistry adopted carbon 12 as the new basis.
At ordinary temperature and pressure, pure O₂ is a colorless, odorless gas. Liquid oxygen is pale blue and strongly paramagnetic. Solid oxygen is also blue at low temperature and has several pressure- and temperature-dependent phases.
Elemental O₂ is used in steelmaking, nonferrous metal refining, welding and cutting, chemical oxidation, wastewater treatment, pulp bleaching, and medical and emergency breathing systems. Liquid oxygen is a major oxidizer in rocketry. Enriched oxygen improves combustion efficiency in some furnaces. Ozone O₃ is used as a strong oxidant for water treatment, odor control, and selected chemical processes, but it must be generated near the point of use because it decomposes readily.
Oxygen is a highly reactive element and is capable of combining with most other elements. It is required by most living organisms and for most forms of combustion. Impurities in molten pig iron are burned away with streams of high pressure oxygen to produce steel. Oxygen can also be combined with acetylene (C2H2) to produce an extremely hot flame used for welding. Liquid oxygen, when combined with liquid hydrogen, makes an excellent rocket fuel. Ozone (O3) forms a thin, protective layer around the earth that shields the surface from the sun's ultraviolet radiation. Oxygen is also a component of hundreds of thousands of organic compounds.
Plants and animals rely on oxygen for respiration. Hospitals frequently prescribe oxygen for patients with respiratory ailments.
Isotopes in Earth/Planetary Science
Molecules, atoms, and ions of the stable isotopes of oxygen possess slightly different physical and chemical properties, and they commonly will be fractionated during physical, chemical, and biological processes, giving rise to variations in isotopic abundances and in atomic weights. There are substantial variations in the isotopic abundances of oxygen in natural terrestrial materials (Fig. IUPAC.8.1). These variations are useful in investigating the origin of substances and studying environmental, hydrological, and geological processes [13] M. W. Wieser, T. B. Coplen. Pure Appl Chem.83, 359 (2011)..
A primary use of stable oxygen isotopes is in isotope hydrology. Although the evolution of the stable hydrogen and oxygen isotopic composition of precipitation begins with the evaporation of water from the oceans, their local and global relationship arises primarily from equilibrium isotopic fractionation of heavier (2H and 18O) and lighter isotopes (1H and 16O) of hydrogen and oxygen during condensation as a tropospheric vapor mass follows a trajectory to higher latitudes and over continents [14] W. Dansgaard. Tellus16, 436 (1964)., [15] I. D. Clark, P. Fritz. Environmental Isotopes in Hydrogeology, p. 328, Lewis Publishers, New York (1997).. As a consequence, the isotopic composition and atomic weight of oxygen in precipitation, rivers, and tap waters varies with elevation, season, and distance from the ocean-continent boundary. Figure 4.8.2 shows the variation in stable oxygen isotopic composition of water from rivers across the United States. These variations in oxygen isotopic composition of environmental water are often combined with hydrogen isotopic compositions and have been used to identify the origin of water and to investigate the interaction between groundwater and surface water (e.g. lakes, streams, and rivers) [16] C. Kendall, T. B. Coplen. Hydrol. Processes.15, 1363 (2011)..
Isotopes in Forensic Science and Anthropology
Measurements of relative 18O abundances have been used to determine the breeding grounds of many species of migrant songbirds. These species of songbirds only grow their feathers before migration, and they grow them on or close to their breeding grounds. Therefore, the isotopic composition of a bird’s feathers correlates to the isotopic signature of the growing season’s precipitation [19] K. A. Hobson. Oecologia120, 314 (1999)., [20] K. A. Hobson, L. I. Wassenaar. Oecologia.109, 142 (1996)..
Measurements of relative 18O abundances of human hair or nail samples collected at archeological sites have been used to determine the geographic region in which a subject lived based on the oxygen isotopic composition of the water they drank (Fig. IUPAC.8.3). This is possible because hair stores a daily record of oxygen isotopic composition of intake water, which correlates to local meteoric water [92] D. M. O’Brien, M. J. Woller. Rapid Commun. Mass Spectrom.21, 2422 (2007)..
Isotopes in Medicine
16O is used to produce radioactive 13N via the 16O (p, 4He) 13N reaction for imaging in positron emission tomography (PET) and to study blood flow through the heart (myocardial perfusion) [94] International Atomic Energy Agency. Cyclotron Produced Radionuclides: Physical Characteristics and Production Methods, Technical Reports Series No. 468. International Atomic Energy Agency Vienna (2009)., [95] M. Sajjad, R. M. Lambrecht, A. P. Wolf. Radiochim. Acta39, 165 (1986)..
17O has been used as a tracer to study cerebral oxygen utilization [96] T. Arai, S. Nakao, K. Mori, K. Ishimori, I. Morishima, T. Miyazawa, B. Fritz-Zieroth. Rapid Commun. Mass Spectrom.169, 153 (1990).. Variations in stable oxygen and hydrogen isotopes are used in energy expenditure studies in animals and humans. The subject is administered a dose of doubly labeled water (water enriched in both 2H and 18O). Measurements of the elimination rates of 2H and 18O in the subject over time through regular sampling of body water (by sampling saliva, urine, or blood) provide information on energy expenditure because the hydrogen isotopic composition of body water is affected primarily by water loss (mainly urination), but the oxygen isotopic composition is affected by both respiration and water loss [97] J. R. Speakman. Theory and Practice, Doubly Labelled Water. Springer Scientific, London (1997)..
Oxygen commonly has oxidation state −2 in oxides and silicates, −1 in peroxides such as hydrogen peroxide H₂O₂, and −1/2 in superoxides such as potassium superoxide KO₂. In water H₂O it forms extensive hydrogen-bonded networks. Oxygen also forms carbon dioxide CO₂, sulfur dioxide SO₂, nitrates, phosphates, carbonates, and many organic functional groups. Positive oxidation states occur only with more electronegative fluorine, as in oxygen difluoride OF₂.
Ozone (O3), a highly active compound, is formed by the action of an electrical discharge or ultraviolet light on oxygen.
Ozone's presence in the atmosphere (amounting to the equivalent of a layer 3 mm thick under ordinary pressures and temperatures) helps prevent harmful ultraviolet rays of the sun from reaching the earth's surface. Pollutants in the atmosphere may have a detrimental effect on this ozone layer. Ozone is toxic and exposure should not exceed 0.2 mg/m# (8-hour time-weighted average - 40-hour work week). Undiluted ozone has a bluish color. Liquid ozone is bluish black and solid ozone is violet-black.
Oxygen, which is very reactive, is a component of hundreds of thousands of organic compounds and combines with most elements.
See more information at the Oxygen compound page.
O₂ is not flammable, but oxygen enrichment greatly increases the speed and severity of fires and can cause materials that normally burn slowly to ignite violently. Liquid oxygen can cause severe cold burns and can make porous materials dangerously oxygen-rich. Ozone O₃ is toxic by inhalation and irritates the respiratory tract. High partial pressures of oxygen can be harmful, especially in diving, hyperbaric, and intensive-care settings.
Oxygen cycles through photosynthesis, respiration, weathering, combustion, and exchange between the atmosphere and oceans. Most atmospheric O₂ is maintained by oxygenic photosynthesis, while much of Earth’s oxygen inventory is locked in rocks as oxides, silicates, and carbonates. Dissolved oxygen controls the habitability of waters for many organisms and is depleted by decay of organic matter and some pollution events.
Industrial oxygen is produced mainly by cryogenic fractional distillation of air where large volumes and high purity are required. Pressure-swing adsorption and membrane systems supply smaller or on-site needs at lower purities. Demand is tied to steel, chemicals, refining, healthcare, water treatment, and aerospace. Because air is the feedstock, cost is dominated by energy, plant scale, purity, transport, and storage rather than geological scarcity. Oxygen itself is not recycled as a commodity, although efficient process design reduces consumption.
Oxygen is the third most abundant element found in the sun, and it plays a part in the carbon-nitrogen cycle, the process once thought to give the sun and stars their energy. Oxygen under excited conditions is responsible for the bright red and yellow-green colors of the Aurora Borealis.
A gaseous element, oxygen forms 21% of the atmosphere by volume and is obtained by liquefaction and fractional distillation. The atmosphere of Mars contains about 0.15% oxygen. The element and its compounds make up 49.2%, by weight, of the earth's crust. About two thirds of the human body and nine tenths of water is oxygen.
In the laboratory it can be prepared by the electrolysis of water or by heating potassium chlorate with manganese dioxide as a catalyst.
Oxygen is one of the most abundant elements in the universe and is made chiefly by helium and carbon burning in massive stars, then dispersed by stellar winds and supernovae. It is common in planets, dust, ices, and rocky minerals. In the Solar System it is a major component of water ice, silicate rock, carbon dioxide ice or gas, and many metal oxides.
- Liquid oxygen is attracted to a magnet strongly enough to be visibly held between magnet poles.
- Ozone in the stratosphere absorbs much biologically damaging ultraviolet radiation.
- Most oxygen atoms on Earth are in minerals, not in the atmosphere.
- The name oxygen originally reflected the mistaken idea that it was required to make all acids.
- Singlet oxygen is an electronically excited form important in photochemistry and some biological damage.
- Hemoglobin binds O₂ reversibly through iron centers rather than by oxidizing iron completely.
Images
Properties
Physical
- Atomic radius (empirical)
- 60 pm Compare Atomic radius (empirical) of all elements →
- Covalent radius
- 66 pm Compare Covalent radius of all elements →
- Van der Waals radius
- 152 pm Compare Van der Waals radius of all elements →
- Density
- 1.429 kg/m³ Compare Density of all elements →
- Molar volume
- 0.014 L/mol
- Phase at STP
- Gas Compare Phase at STP of all elements →
- Melting point
- -218.79 °C Compare Melting point of all elements →
- Boiling point
- -182.95 °C Compare Boiling point of all elements →
- Thermal conductivity
- 0.027 W/(m·K) Compare Thermal conductivity of all elements →
- Specific heat capacity
- 0.918 J/(g·K) Compare Specific heat capacity of all elements →
- Molar heat capacity
- 29.378 J/(mol·K) Compare Molar heat capacity of all elements →
- Crystal structure
- Cubic Compare Crystal structure of all elements →
Chemical
- Electronegativity (Pauling)
- 3.44 Compare Electronegativity (Pauling) of all elements →
- Electronegativity (Allen)
- 3.61
- Electron affinity
- 1.4611 eV
- Ionization energy (1st)
- 13.618055 eV Compare Ionization energy (1st) of all elements →
- Ionization energy (2nd)
- 35.121241 eV Compare Ionization energy (2nd) of all elements →
- Ionization energy (3rd)
- 54.935729 eV Compare Ionization energy (3rd) of all elements →
- Ionization energy (4th)
- 77.413766 eV Compare Ionization energy (4th) of all elements →
- Ionization energy (5th)
- 113.899392 eV Compare Ionization energy (5th) of all elements →
- Oxidation states
- −2, −1, 0, +1, +2 Compare Oxidation states of all elements →
- Valence electrons
- 6 Compare Valence electrons of all elements →
- Electron configuration
- [He] 2s2 2p4
Thermodynamic
- Triple point (temperature)
- -218.7916 °C
- Triple point (pressure)
- 146.3 Pa
- Critical point (temperature)
- -118.569 °C
- Critical point (pressure)
- 5.043e+6 Pa
- Heat of fusion
- 0.00460175 eV Compare Heat of fusion of all elements →
- Heat of vaporization
- 0.07068456 eV Compare Heat of vaporization of all elements →
- Heat of atomization
- 2.582474 eV
- Atomization enthalpy
- 2.583085 eV
Nuclear
- Protons
- 8 Compare Protons of all elements →
- Neutrons
- 8 Compare Neutrons of all elements →
- Known isotopes
- 18 Compare Known isotopes of all elements →
- Stable isotopes
- 3 Compare Stable isotopes of all elements →
- Most stable isotope
- O-16
- Discovery year
- 1771
Abundance
- Abundance (Earth's crust)
- 4.61e+5 mg/kg Compare Abundance (Earth's crust) of all elements →
- Abundance (ocean)
- 8.57 × 105 mg/L Compare Abundance (ocean) of all elements →
Crystal Structure
- Lattice constant a
- 683 pm
Electronic Structure
- Electrons per shell
- 2, 6 Compare Electrons per shell of all elements →
Identifiers
- CAS number
- 7782-44-7 Compare CAS number of all elements →
- Term symbol
- 3P2
- InChI
- InChI=1S/O
- InChI Key
- QVGXLLKOCUKJST-UHFFFAOYSA-N
Electron Configuration Measured
O: 2s² 2p⁴[He] 2s² 2p⁴1s² 2s² 2p⁴Atomic model
Isotopes change neutron count, mass, and stability — not the electron configuration of a neutral atom.
Schematic atomic model, not to scale.
Atomic Fingerprint
Emission / Absorption Spectrum
Isotope Distribution
| Mass number | Atomic mass (u) | Natural abundance | Half-life |
|---|---|---|---|
| 16 Stable | 15.99491461957 ± 0.00000000017 | 99.7570% | Stable |
| 17 Stable | 16.9991317565 ± 0.00000000069 | 0.0380% | Stable |
| 18 Stable | 17.99915961286 ± 0.00000000076 | 0.2050% | Stable |
Phase / State
Reason: 207.9 °C above boiling point (-182.95 °C)
Schematic, not to scale
Phase transition points
Transition energies
Energy required to melt 1 mol at melting point
Energy required to vaporize 1 mol at boiling point
Density
At standard conditions
Estimated via ideal gas law at current T
Advanced
Atomic Spectra
Lines Holdings ?
| Ion | Charge | Total lines | Transition probabilities | Level designations |
|---|---|---|---|---|
| O I | 0 | 910 | 854 | 907 |
| O II | +1 | 1630 | 876 | 1630 |
| O III | +2 | 1005 | 974 | 974 |
| O IV | +3 | 1525 | 1521 | 1523 |
| O V | +4 | 391 | 385 | 385 |
| O VI | +5 | 157 | 126 | 157 |
| O VII | +6 | 189 | 188 | 189 |
| O VIII | +7 | 137 | 137 | 137 |
Levels Holdings ?
| Ion | Charge | Levels |
|---|---|---|
| O I | 0 | 614 |
| O II | +1 | 287 |
| O III | +2 | 188 |
| O IV | +3 | 219 |
| O V | +4 | 172 |
| O VI | +5 | 148 |
| O VII | +6 | 149 |
| O VIII | +7 | 149 |
Ionic Radii
| Charge | Coordination | Spin | Radius |
|---|---|---|---|
| -2 | 2 | N/A | 135 pm |
| -2 | 3 | N/A | 136 pm |
| -2 | 4 | N/A | 138 pm |
| -2 | 6 | N/A | 140 pm |
| -2 | 8 | N/A | 142 pm |
Compounds
Isotopes (3)
Oxygen has nine isotopes. Natural oxygen is a mixture of three isotopes.
| Mass number | Atomic mass (u) | Natural abundance | Half-life | Decay mode | |
|---|---|---|---|---|---|
| 16 Stable | 15.99491461957 ± 0.00000000017 | 99.7570% ± 0.0160% | Stable | stable | |
| 17 Stable | 16.9991317565 ± 0.00000000069 | 0.0380% ± 0.0010% | Stable | stable | |
| 18 Stable | 17.99915961286 ± 0.00000000076 | 0.2050% ± 0.0140% | Stable | stable |
Spectral Lines
Showing 50 of 1013. Only spectral lines with measured intensity are shown by default.
| Wavelength (nm) | Intensity | Ion stage | Type | Transition | Accuracy | Source | |
|---|---|---|---|---|---|---|---|
| 615.8187 nm | 490 | O I | emission | 2s2.2p3.(4S*).3p 5P → 2s2.2p3.(4S*).4d 5D* | Measured | NIST | |
| 615.6778 nm | 450 | O I | emission | 2s2.2p3.(4S*).3p 5P → 2s2.2p3.(4S*).4d 5D* | Measured | NIST | |
| 700.223 nm | 450 | O I | emission | 2s2.2p3.(4S*).3p 3P → 2s2.2p3.(4S*).4d 3D* | Measured | NIST | |
| 725.4448 nm | 450 | O I | emission | 2s2.2p3.(4S*).3p 3P → 2s2.2p3.(4S*).5s 3S* | Measured | NIST | |
| 615.5971 nm | 400 | O I | emission | 2s2.2p3.(4S*).3p 5P → 2s2.2p3.(4S*).4d 5D* | Measured | NIST | |
| 645.5977 nm | 400 | O I | emission | 2s2.2p3.(4S*).3p 5P → 2s2.2p3.(4S*).5s 5S* | Measured | NIST | |
| 725.4154 nm | 400 | O I | emission | 2s2.2p3.(4S*).3p 3P → 2s2.2p3.(4S*).5s 3S* | Measured | NIST | |
| 645.4444 nm | 360 | O I | emission | 2s2.2p3.(4S*).3p 5P → 2s2.2p3.(4S*).5s 5S* | Measured | NIST | |
| 700.1922 nm | 360 | O I | emission | 2s2.2p3.(4S*).3p 3P → 2s2.2p3.(4S*).4d 3D* | Measured | NIST | |
| 645.3602 nm | 320 | O I | emission | 2s2.2p3.(4S*).3p 5P → 2s2.2p3.(4S*).5s 5S* | Measured | NIST | |
| 725.4531 nm | 320 | O I | emission | 2s2.2p3.(4S*).3p 3P → 2s2.2p3.(4S*).5s 3S* | Measured | NIST | |
| 715.6701 nm | 210 | O I | emission | 2s2.2p3.(2D*).3s 1D* → 2s2.2p3.(2D*).3p 1D | Measured | NIST | |
| 396.1573 nm | 200 | O III | emission | 2s2.2p.(2P*).3p 1D → 2s2.2p.(2P*).3d 1F* | Measured | NIST | |
| 533.0741 nm | 190 | O I | emission | 2s2.2p3.(4S*).3p 5P → 2s2.2p3.(4S*).5d 5D* | Measured | NIST | |
| 604.6438 nm | 190 | O I | emission | 2s2.2p3.(4S*).3p 3P → 2s2.2p3.(4S*).6s 3S* | Measured | NIST | |
| 394.72949 nm | 185 | O I | emission | 2s2.2p3.(4S*).3s 5S* → 2s2.2p3.(4S*).4p 5P | Measured | NIST | |
| 394.74813 nm | 160 | O I | emission | 2s2.2p3.(4S*).3s 5S* → 2s2.2p3.(4S*).4p 5P | Measured | NIST | |
| 532.9681 nm | 160 | O I | emission | 2s2.2p3.(4S*).3p 5P → 2s2.2p3.(4S*).5d 5D* | Measured | NIST | |
| 604.6233 nm | 160 | O I | emission | 2s2.2p3.(4S*).3p 3P → 2s2.2p3.(4S*).6s 3S* | Measured | NIST | |
| 394.75862 nm | 140 | O I | emission | 2s2.2p3.(4S*).3s 5S* → 2s2.2p3.(4S*).4p 5P | Measured | NIST | |
| 543.6862 nm | 135 | O I | emission | 2s2.2p3.(4S*).3p 5P → 2s2.2p3.(4S*).6s 5S* | Measured | NIST | |
| 559.789 nm | 130 | O V | emission | 1s2.2s.3p 3P* → 1s2.2s.3d 3D | Measured | NIST | |
| 650.024 nm | 130 | O V | emission | 1s2.2p.(2P*<3/2>).3p 3D → 1s2.2p.(2P*<3/2>).3d 3F* | Measured | NIST | |
| 382.34136 nm | 120 | O I | emission | 2s2.2p3.(2D*).3s 3D* → 2s2.2p3.(2P*).3p 3D | Measured | NIST | |
| 557.7339 nm | 120 | O I | emission | 2s2.2p4 1D → 2s2.2p4 1S | Measured | NIST | |
| 543.5775 nm | 110 | O I | emission | 2s2.2p3.(4S*).3p 5P → 2s2.2p3.(4S*).6s 5S* | Measured | NIST | |
| 559.2252 nm | 110 | O III | emission | 2s2.2p.(2P*).3s 1P* → 2s2.2p.(2P*).3p 1P | Measured | NIST | |
| 604.6495 nm | 110 | O I | emission | 2s2.2p3.(4S*).3p 3P → 2s2.2p3.(4S*).6s 3S* | Measured | NIST | |
| 395.46067 nm | 100 | O I | emission | 2s2.2p3.(4S*).3p 3P → 2s2.2p3.(2P*).3s 3P* | Measured | NIST | |
| 412.396 nm | 100 | O V | emission | 1s2.2p.(2P*<3/2>).3s 3P* → 1s2.2p.(2P*<3/2>).3p 3D | Measured | NIST | |
| 436.8258 nm | 100 | O I | emission | 2s2.2p3.(4S*).3s 3S* → 2s2.2p3.(4S*).4p 3P | Measured | NIST | |
| 543.5178 nm | 90 | O I | emission | 2s2.2p3.(4S*).3p 5P → 2s2.2p3.(4S*).6s 5S* | Measured | NIST | |
| 423.3274 nm | 80 | O I | emission | 2s2.2p3.(4S*).4p 3P → 2s2.2p3.(2D*<3/2>).3d 3P* | Measured | NIST | |
| 441.4899 nm | 27 | O II | emission | 2s2.2p2.(3P).3s 2P → 2s2.2p2.(3P).3p 2D* | Measured | NIST | |
| 672.1388 nm | 26 | O II | emission | 2s2.2p2.(3P).3s 2P → 2s2.2p2.(3P).3p 2S* | Measured | NIST | |
| 441.6975 nm | 25 | O II | emission | 2s2.2p2.(3P).3s 2P → 2s2.2p2.(3P).3p 2D* | Measured | NIST | |
| 397.3256 nm | 24 | O II | emission | 2s2.2p2.(3P).3s 2P → 2s2.2p2.(3P).3p 2P* | Measured | NIST | |
| 407.58617 nm | 24 | O II | emission | 2s2.2p2.(3P).3p 4D* → 2s2.2p2.(3P).3d 4F | Measured | NIST | |
| 464.91347 nm | 24 | O II | emission | 2s2.2p2.(3P).3s 4P → 2s2.2p2.(3P).3p 4D* | Measured | NIST | |
| 664.1031 nm | 24 | O II | emission | 2s2.2p2.(3P).3s 2P → 2s2.2p2.(3P).3p 2S* | Measured | NIST | |
| 407.21525 nm | 23 | O II | emission | 2s2.2p2.(3P).3p 4D* → 2s2.2p2.(3P).3d 4F | Measured | NIST | |
| 434.9426 nm | 23 | O II | emission | 2s2.2p2.(3P).3s 4P → 2s2.2p2.(3P).3p 4P* | Measured | NIST | |
| 411.92165 nm | 22 | O II | emission | 2s2.2p2.(3P).3p 4P* → 2s2.2p2.(3P).3d 4D | Measured | NIST | |
| 459.0974 nm | 22 | O II | emission | 2s2.2p2.(1D).3s 2D → 2s2.2p2.(1D).3p 2F* | Measured | NIST | |
| 464.18103 nm | 22 | O II | emission | 2s2.2p2.(3P).3s 4P → 2s2.2p2.(3P).3p 4D* | Measured | NIST | |
| 689.5102 nm | 22 | O II | emission | 2s2.2p2.(3P).3d 4F → 2s2.2p2.(3P).4p 4D* | Measured | NIST | |
| 406.98819 nm | 21 | O II | emission | 2s2.2p2.(3P).3p 4D* → 2s2.2p2.(3P).3d 4F | Measured | NIST | |
| 435.126 nm | 21 | O II | emission | 2s2.2p2.(1D).3s 2D → 2s2.2p2.(1D).3p 2D* | Measured | NIST | |
| 466.16324 nm | 21 | O II | emission | 2s2.2p2.(3P).3s 4P → 2s2.2p2.(3P).3p 4D* | Measured | NIST | |
| 470.5346 nm | 21 | O II | emission | 2s2.2p2.(3P).3p 2D* → 2s2.2p2.(3P).3d 2F | Measured | NIST |
Extended Properties
Covalent Radii (Extended)
- Covalent radius (Pyykkö)
- 63 pm
- Covalent radius (Pyykkö, double)
- 57 pm
- Covalent radius (Pyykkö, triple)
- 53 pm
- Covalent radius (Bragg)
- 65 pm
Van der Waals Radii
- Bondi
- 152 pm
- Batsanov
- 155 pm
- Alvarez
- 150 pm
- UFF
- 350 pm
- MM3
- 182 pm
- Dreiding
- 340.46 pm
- Rowland–Taylor
- 158 pm
Atomic & Metallic Radii
- Atomic radius (Rahm)
- 171 pm
Numbering Scales
- Mendeleev
- 99
- Pettifor
- 101
- Glawe
- 97
Electronegativity Scales
- Ghosh
- 0
- Gunnarsson–Lundqvist
- 8
- Robles–Bartolotti
- 6
Polarizability & Dispersion
- Dipole polarizability
- 5.3 a.u.
- Dipole polarizability (unc.)
- 0.2 a.u.
- C₆
- 15.6 Ha·Bohr6
- C₆ (Gould–Bučko)
- 16.7 Ha·Bohr6
Chemical Affinity
- Proton affinity
- 485.2 kJ/mol
- Gas basicity
- 459.6 kJ/mol
Phase Transitions & Allotropes
| Melting point | 54.36 K |
| Boiling point | 90.19 K |
| Critical point (temperature) | 154.58 K |
| Critical point (pressure) | 5.04 MPa |
| Triple point (temperature) | 54.36 K |
| Triple point (pressure) | 0.15 kPa |
Oxidation State Categories
Advanced Reference Data
Screening Constants (3)
| n | Orbital | σ |
|---|---|---|
| 1 | s | 0.3421 |
| 2 | p | 3.5468 |
| 2 | s | 3.5084 |
Crystal Radii Detail (5)
| Charge | CN | Spin | rcrystal (pm) | Origin |
|---|---|---|---|---|
| -2 | II | 121 | ||
| -2 | III | 122 | ||
| -2 | IV | 124 | ||
| -2 | VI | 126 | ||
| -2 | VIII | 128 |
Isotope Decay Modes (22)
| Isotope | Mode | Intensity |
|---|---|---|
| 11 | 2p | 100% |
| 12 | 2p | 100% |
| 13 | B+ | 100% |
| 13 | B+p | 10.9% |
| 14 | B+ | 100% |
| 15 | B+ | 100% |
| 19 | B- | 100% |
| 20 | B- | 100% |
| 21 | B- | 100% |
| 21 | B-n | — |
X‑ray Scattering Factors (502)
| Energy (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 0.70328 |
| 10.1617 | — | 0.70723 |
| 10.3261 | — | 0.70738 |
| 10.4931 | — | 0.70753 |
| 10.6628 | — | 0.70768 |
| 10.8353 | — | 0.70783 |
| 11.0106 | — | 0.70798 |
| 11.1886 | — | 0.70813 |
| 11.3696 | — | 0.70828 |
| 11.5535 | — | 0.70843 |
Additional Data
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
4.61×105 milligrams per kilogram
References (1)
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
8.57×105 milligrams per liter
References (1)
Sources
Sources of this element.
Oxygen is the third most abundant element found in the sun, and it plays a part in the carbon-nitrogen cycle, the process once thought to give the sun and stars their energy. Oxygen under excited conditions is responsible for the bright red and yellow-green colors of the Aurora Borealis.
A gaseous element, oxygen forms 21% of the atmosphere by volume and is obtained by liquefaction and fractional distillation. The atmosphere of Mars contains about 0.15% oxygen. The element and its compounds make up 49.2%, by weight, of the earth's crust. About two thirds of the human body and nine tenths of water is oxygen.
In the laboratory it can be prepared by the electrolysis of water or by heating potassium chlorate with manganese dioxide as a catalyst.
References (1)
- [6] Oxygen https://periodic.lanl.gov/8.shtml
Isotopes in Forensic Science and Anthropology
Information on the use of this element's isotopes in forensic science and anthropology.
Measurements of relative 18O abundances have been used to determine the breeding grounds of many species of migrant songbirds. These species of songbirds only grow their feathers before migration, and they grow them on or close to their breeding grounds. Therefore, the isotopic composition of a bird’s feathers correlates to the isotopic signature of the growing season’s precipitation [19] K. A. Hobson. Oecologia120, 314 (1999)., [20] K. A. Hobson, L. I. Wassenaar. Oecologia.109, 142 (1996)..
Measurements of relative 18O abundances of human hair or nail samples collected at archeological sites have been used to determine the geographic region in which a subject lived based on the oxygen isotopic composition of the water they drank (Fig. IUPAC.8.3). This is possible because hair stores a daily record of oxygen isotopic composition of intake water, which correlates to local meteoric water [92] D. M. O’Brien, M. J. Woller. Rapid Commun. Mass Spectrom.21, 2422 (2007)..
References (7)
- [14] W. Dansgaard. Tellus16, 436 (1964).
- [15] I. D. Clark, P. Fritz. Environmental Isotopes in Hydrogeology, p. 328, Lewis Publishers, New York (1997).
- [19] K. A. Hobson. Oecologia120, 314 (1999).
- [20] K. A. Hobson, L. I. Wassenaar. Oecologia.109, 142 (1996).
- [92] D. M. O’Brien, M. J. Woller. Rapid Commun. Mass Spectrom.21, 2422 (2007).
- [93] I. Fraser, W. Meier-Augenstein, R. M. Kalin. Rapid Commun. Mass Spectrom.20, 1109 (2006).
- [4] IUPAC Periodic Table of the Elements and Isotopes (IPTEI) https://doi.org/10.1515/pac-2015-0703
References
(9)
Data deposited in or computed by PubChem
The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.
Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.
The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.
Thomas Jefferson National Accelerator Facility (Jefferson Lab) is one of 17 national laboratories funded by the U.S. Department of Energy. The lab's primary mission is to conduct basic research of the atom's nucleus using the lab's unique particle accelerator, known as the Continuous Electron Beam Accelerator Facility (CEBAF). For more information visit https://www.jlab.org/
The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.
The periodic table contains NIST's critically-evaluated data on atomic properties of the elements. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database
This section provides all form of data related to element Oxygen.
The element property data was retrieved from publications.