Difference between revisions of "Oxygen"
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|alt name= | |alt name= | ||
|alt names= | |alt names= | ||
| − | |allotropes= | + | |allotropes=Dioxygen, [[ozone]], tetraoxygen |
|appearance=Colorless (gas)<br>Blueish liquid (liquid) | |appearance=Colorless (gas)<br>Blueish liquid (liquid) | ||
<!-- Periodic table --> | <!-- Periodic table --> | ||
| Line 27: | Line 27: | ||
|right=[[Fluorine]] | |right=[[Fluorine]] | ||
|number=8 | |number=8 | ||
| − | |atomic mass= | + | |atomic mass=15.999 |
|atomic mass 2= | |atomic mass 2= | ||
|atomic mass ref= | |atomic mass ref= | ||
| Line 35: | Line 35: | ||
|series comment= | |series comment= | ||
|series color= | |series color= | ||
| − | |group= | + | |group=16 |
|group ref= | |group ref= | ||
| − | |group comment= | + | |group comment=(chalcogens) |
| − | |period= | + | |period=2 |
|period ref= | |period ref= | ||
|period comment= | |period comment= | ||
| − | |block= | + | |block=p |
|block ref= | |block ref= | ||
|block comment= | |block comment= | ||
| − | |electron configuration= | + | |electron configuration=[He] 2s<sup>2</sup> 2p<sup>4</sup> |
|electron configuration ref= | |electron configuration ref= | ||
|electron configuration comment= | |electron configuration comment= | ||
| − | |electrons per shell= | + | |electrons per shell=2, 6 |
|electrons per shell ref= | |electrons per shell ref= | ||
|electrons per shell comment= | |electrons per shell comment= | ||
| Line 53: | Line 53: | ||
|physical properties comment= | |physical properties comment= | ||
|color=Colorless | |color=Colorless | ||
| − | |phase= | + | |phase=Gas |
|phase ref= | |phase ref= | ||
|phase comment= | |phase comment= | ||
| − | |melting point K= | + | |melting point K=54.36 |
| − | |melting point C= | + | |melting point C=−218.79 |
| − | |melting point F= | + | |melting point F=−361.82 |
|melting point ref= | |melting point ref= | ||
|melting point comment= | |melting point comment= | ||
| − | |boiling point K= | + | |boiling point K=90.188 |
| − | |boiling point C= | + | |boiling point C=−182.962 |
| − | |boiling point F= | + | |boiling point F=−297.332 |
|boiling point ref= | |boiling point ref= | ||
|boiling point comment= | |boiling point comment= | ||
| Line 71: | Line 71: | ||
|sublimation point ref= | |sublimation point ref= | ||
|sublimation point comment= | |sublimation point comment= | ||
| − | |density gplstp= | + | |density gplstp=1.429 |
|density gplstp ref= | |density gplstp ref= | ||
|density gplstp comment= | |density gplstp comment= | ||
| Line 86: | Line 86: | ||
|density gpcm3mp ref= | |density gpcm3mp ref= | ||
|density gpcm3mp comment= | |density gpcm3mp comment= | ||
| − | |density gpcm3bp= | + | |density gpcm3bp=1.141 |
|density gpcm3bp ref= | |density gpcm3bp ref= | ||
|density gpcm3bp comment= | |density gpcm3bp comment= | ||
| Line 93: | Line 93: | ||
|molar volume ref= | |molar volume ref= | ||
|molar volume comment= | |molar volume comment= | ||
| − | |triple point K= | + | |triple point K=54.361 |
| − | |triple point kPa= | + | |triple point kPa=0.1463 |
|triple point ref= | |triple point ref= | ||
|triple point comment= | |triple point comment= | ||
| Line 101: | Line 101: | ||
|triple point 2 ref= | |triple point 2 ref= | ||
|triple point 2 comment= | |triple point 2 comment= | ||
| − | |critical point K= | + | |critical point K=154.581 |
| − | |critical point MPa= | + | |critical point MPa=5.043 |
|critical point ref= | |critical point ref= | ||
|critical point comment= | |critical point comment= | ||
| − | |heat fusion= | + | |heat fusion=0.444 |
|heat fusion ref= | |heat fusion ref= | ||
|heat fusion comment= | |heat fusion comment= | ||
| Line 111: | Line 111: | ||
|heat fusion 2 ref= | |heat fusion 2 ref= | ||
|heat fusion 2 comment= | |heat fusion 2 comment= | ||
| − | |heat vaporization= | + | |heat vaporization=6.82 |
|heat vaporization ref= | |heat vaporization ref= | ||
|heat vaporization comment= | |heat vaporization comment= | ||
| − | |heat capacity= | + | |heat capacity=29.378 |
|heat capacity ref= | |heat capacity ref= | ||
|heat capacity comment= | |heat capacity comment= | ||
| Line 123: | Line 123: | ||
|vapor pressure 10= | |vapor pressure 10= | ||
|vapor pressure 100= | |vapor pressure 100= | ||
| − | |vapor pressure 1 k= | + | |vapor pressure 1 k=61 |
| − | |vapor pressure 10 k= | + | |vapor pressure 10 k=73 |
| − | |vapor pressure 100 k= | + | |vapor pressure 100 k=90 |
|vapor pressure ref= | |vapor pressure ref= | ||
|vapor pressure comment= | |vapor pressure comment= | ||
| Line 138: | Line 138: | ||
<!-- Atomic properties --> | <!-- Atomic properties --> | ||
|atomic properties comment= | |atomic properties comment= | ||
| − | |oxidation states= | + | |oxidation states=2, 1, −1, '''−2''' |
|oxidation states ref= | |oxidation states ref= | ||
|oxidation states comment= | |oxidation states comment= | ||
| − | |electronegativity= | + | |electronegativity=3.44 |
|electronegativity ref= | |electronegativity ref= | ||
|electronegativity comment= | |electronegativity comment= | ||
| − | |ionization energy 1= | + | |ionization energy 1=1313.9 |
|ionization energy 1 ref= | |ionization energy 1 ref= | ||
|ionization energy 1 comment= | |ionization energy 1 comment= | ||
| − | |ionization energy 2= | + | |ionization energy 2=3388.3 |
|ionization energy 2 ref= | |ionization energy 2 ref= | ||
|ionization energy 2 comment= | |ionization energy 2 comment= | ||
| − | |ionization energy 3= | + | |ionization energy 3=5300.5 |
|ionization energy 3 ref= | |ionization energy 3 ref= | ||
|ionization energy 3 comment= | |ionization energy 3 comment= | ||
| Line 162: | Line 162: | ||
|atomic radius calculated ref= | |atomic radius calculated ref= | ||
|atomic radius calculated comment= | |atomic radius calculated comment= | ||
| − | |covalent radius= | + | |covalent radius=66±2 |
|covalent radius ref= | |covalent radius ref= | ||
|covalent radius comment= | |covalent radius comment= | ||
| − | |Van der Waals radius= | + | |Van der Waals radius=152 |
|Van der Waals radius ref= | |Van der Waals radius ref= | ||
|Van der Waals radius comment= | |Van der Waals radius comment= | ||
| Line 172: | Line 172: | ||
|crystal structure prefix= | |crystal structure prefix= | ||
|crystal structure ref= | |crystal structure ref= | ||
| − | |crystal structure comment= | + | |crystal structure comment=Cubic |
|crystal structure 2= | |crystal structure 2= | ||
|crystal structure 2 prefix= | |crystal structure 2 prefix= | ||
| Line 179: | Line 179: | ||
|speed of sound= | |speed of sound= | ||
|speed of sound ref= | |speed of sound ref= | ||
| − | |speed of sound comment= | + | |speed of sound comment=330 m/s (gas, at 27 °C) |
|speed of sound rod at 20= | |speed of sound rod at 20= | ||
|speed of sound rod at 20 ref= | |speed of sound rod at 20 ref= | ||
| Line 192: | Line 192: | ||
|thermal expansion at 25 ref= | |thermal expansion at 25 ref= | ||
|thermal expansion at 25 comment= | |thermal expansion at 25 comment= | ||
| − | |thermal conductivity= | + | |thermal conductivity=26.58×10<sup>−3</sup> |
|thermal conductivity ref= | |thermal conductivity ref= | ||
|thermal conductivity comment= | |thermal conductivity comment= | ||
| Line 217: | Line 217: | ||
|Curie point ref= | |Curie point ref= | ||
|Curie point comment= | |Curie point comment= | ||
| − | |magnetic ordering= | + | |magnetic ordering=Paramagnetic |
|magnetic ordering ref= | |magnetic ordering ref= | ||
|magnetic ordering comment= | |magnetic ordering comment= | ||
| Line 247: | Line 247: | ||
|Brinell hardness ref= | |Brinell hardness ref= | ||
|Brinell hardness comment= | |Brinell hardness comment= | ||
| − | |CAS number= | + | |CAS number=7782-44-7 |
|CAS number ref= | |CAS number ref= | ||
|CAS number comment= | |CAS number comment= | ||
| Line 255: | Line 255: | ||
|prediction date ref= | |prediction date ref= | ||
|prediction date= | |prediction date= | ||
| − | |discovered by= | + | |discovered by=Carl Wilhelm Scheele (1771) |
|discovery date ref= | |discovery date ref= | ||
|discovery date= | |discovery date= | ||
| Line 262: | Line 262: | ||
|first isolation date= | |first isolation date= | ||
|discovery and first isolation by= | |discovery and first isolation by= | ||
| − | |named by= | + | |named by= Antoine Lavoisier (1777) |
|named date ref= | |named date ref= | ||
|named date= | |named date= | ||
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|engvar= | |engvar= | ||
}} | }} | ||
| − | '''Oxygen''' is the 8th element on the periodic table and is the second strongest [[oxidizer]], second to fluorine. It has the atomic weight of ~16 (15.9949), but as a gas it is diatomic with a molar mass of ~32. | + | '''Oxygen''' (symbol: '''O''') is the 8th element on the periodic table and is the second strongest [[oxidizer]], second to [[fluorine]]. It has the atomic weight of ~16 (15.9949), but as a gas it is diatomic with a molar mass of ~32. |
==Properties== | ==Properties== | ||
| Line 280: | Line 280: | ||
It is highly electronegative, with a 3.44 on the Pauling scale. It reacts directly with almost every element, a major exception being most of the noble metals and gases (except for [[xenon]]). | It is highly electronegative, with a 3.44 on the Pauling scale. It reacts directly with almost every element, a major exception being most of the noble metals and gases (except for [[xenon]]). | ||
| − | It reacts with many metals to form oxides. These reactions can be slow and gradual (as is the rusting of [[iron]]) or extremely fast, as in the combustion of [[cesium]]. | + | It reacts with many metals to form oxides. These reactions can be slow and gradual (as is the rusting of [[iron]]) or extremely fast, as in the combustion of [[caesium|cesium]]. |
===Physical=== | ===Physical=== | ||
Although in gas form it is indistinguishable from other common gases, in liquid form it is pale blue (and highly reactive). Oxygen is paramagnetic. | Although in gas form it is indistinguishable from other common gases, in liquid form it is pale blue (and highly reactive). Oxygen is paramagnetic. | ||
| + | |||
| + | Oxygen has several allotrope forms, with dioxygen and [[ozone]] (trioxygen) being the most important. | ||
| + | |||
| + | Under normal conditions dioxygen exists in a triplet state denoted by the term symbol <sup>3</sup>Σ<sup>-</sup><sub>g</sub> or simplified chemically <sup>3</sup>O<sub>2</sub>. However, it is possible to create dioxygen in the singlet state usually denoted by <sup>1</sup>Δ<sub>g</sub> (or simplified <sup>1</sup>O<sub>2</sub>) photochemically or from, for example, the reaction of hypochlorite and hydrogen peroxide. At high concentrations of singlet oxygen, a red chemiluminescence is observed when the oxygen returns to the ground state: | ||
| + | |||
| + | : NaOCl + H<sub>2</sub>O<sub>2</sub> → NaCl + H<sub>2</sub>O + <sup>1</sup>O<sub>2</sub> | ||
| + | : <sup>1</sup>O<sub>2</sub> → <sup>3</sup>O<sub>2</sub> + hv | ||
| + | |||
| + | To be precise, two transitions cause the red glow:<ref> P. Lechtken, ''Chemie in unserer Zeit'' '''1974''', 8, 11-16, [https://doi.org/10.1002/ciuz.19740080103 doi:10.1002/ciuz.19740080103]</ref> | ||
| + | |||
| + | : 2 O<sub>2</sub> (<sup>1</sup>Δ<sub>g</sub>) → 2 O<sub>2</sub> (<sup>3</sup>Σ<sup>-</sup><sub>g</sub>) + hv (λ = 633.4 nm) | ||
| + | : O<sub>2</sub> (<sup>3</sup>Σ<sup>+</sup><sub>g</sub>) → O<sub>2</sub> (<sup>3</sup>Σ<sup>-</sup><sub>g</sub>) + hv (λ = 703.2 nm) | ||
==Availability== | ==Availability== | ||
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===Disposal=== | ===Disposal=== | ||
Oxygen can be safely released in open air, but never in closed places. | Oxygen can be safely released in open air, but never in closed places. | ||
| + | |||
| + | ==Gallery== | ||
| + | <gallery widths="200" position="center" columns="4" orientation="none"> | ||
| + | Singlet_oxygen.jpg|Chemiluminescence of singlet oxygen | ||
| + | </gallery> | ||
| + | |||
| + | ==See also== | ||
| + | *[[Ozone]] | ||
==References== | ==References== | ||
Latest revision as of 19:23, 13 August 2022
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|
| General properties | |||||
|---|---|---|---|---|---|
| Name, symbol | Oxygen, O | ||||
| Allotropes | Dioxygen, ozone, tetraoxygen | ||||
| Appearance |
Colorless (gas) Blueish liquid (liquid) | ||||
| Oxygen in the periodic table | |||||
| |||||
| Atomic number | 8 | ||||
| Standard atomic weight (Ar) | 15.999 | ||||
| Group, block | (chalcogens); p-block | ||||
| Period | period 2 | ||||
| Electron configuration | [He] 2s2 2p4 | ||||
per shell | 2, 6 | ||||
| Physical properties | |||||
| Colorless | |||||
| Phase | Gas | ||||
| Melting point | 54.36 K (−218.79 °C, −361.82 °F) | ||||
| Boiling point | 90.188 K (−182.962 °C, −297.332 °F) | ||||
| Density at (0 °C and 101.325 kPa) | 1.429 g/L | ||||
| when liquid, at | 1.141 g/cm3 | ||||
| Triple point | 54.361 K, 0.1463 kPa | ||||
| Critical point | 154.581 K, 5.043 MPa | ||||
| Heat of fusion | 0.444 kJ/mol | ||||
| Heat of | 6.82 kJ/mol | ||||
| Molar heat capacity | 29.378 J/(mol·K) | ||||
| pressure | |||||
| Atomic properties | |||||
| Oxidation states | 2, 1, −1, −2 | ||||
| Electronegativity | Pauling scale: 3.44 | ||||
| energies |
1st: 1313.9 kJ/mol 2nd: 3388.3 kJ/mol 3rd: 5300.5 kJ/mol | ||||
| Covalent radius | 66±2 pm | ||||
| Van der Waals radius | 152 pm | ||||
| Miscellanea | |||||
| Crystal structure | Cubic | ||||
| Speed of sound | 330 m/s (gas, at 27 °C) | ||||
| Thermal conductivity | 26.58×10−3 W/(m·K) | ||||
| Magnetic ordering | Paramagnetic | ||||
| CAS Registry Number | 7782-44-7 | ||||
| History | |||||
| Discovery | Carl Wilhelm Scheele (1771) | ||||
| Named by | Antoine Lavoisier (1777) | ||||
Oxygen (symbol: O) is the 8th element on the periodic table and is the second strongest oxidizer, second to fluorine. It has the atomic weight of ~16 (15.9949), but as a gas it is diatomic with a molar mass of ~32.
Contents
Properties
Chemical
Oxygen has 6 valence electrons and typically exists with two lone pairs of electrons.
It is highly electronegative, with a 3.44 on the Pauling scale. It reacts directly with almost every element, a major exception being most of the noble metals and gases (except for xenon).
It reacts with many metals to form oxides. These reactions can be slow and gradual (as is the rusting of iron) or extremely fast, as in the combustion of cesium.
Physical
Although in gas form it is indistinguishable from other common gases, in liquid form it is pale blue (and highly reactive). Oxygen is paramagnetic.
Oxygen has several allotrope forms, with dioxygen and ozone (trioxygen) being the most important.
Under normal conditions dioxygen exists in a triplet state denoted by the term symbol 3Σ-g or simplified chemically 3O2. However, it is possible to create dioxygen in the singlet state usually denoted by 1Δg (or simplified 1O2) photochemically or from, for example, the reaction of hypochlorite and hydrogen peroxide. At high concentrations of singlet oxygen, a red chemiluminescence is observed when the oxygen returns to the ground state:
- NaOCl + H2O2 → NaCl + H2O + 1O2
- 1O2 → 3O2 + hv
To be precise, two transitions cause the red glow:[1]
- 2 O2 (1Δg) → 2 O2 (3Σ-g) + hv (λ = 633.4 nm)
- O2 (3Σ+g) → O2 (3Σ-g) + hv (λ = 703.2 nm)
Availability
Gaseous oxygen makes up 21% of the atmosphere. For higher concentrations, compressed oxygen can be procured from the companies that sell welding products as well as scuba diving stores. Cryogenic liquid oxygen is harder to get because unlike liquid nitrogen it is a fire and explosive hazard, when it (accidentally) enters in contact with organic materials.
Preparation
Oxygen is extracted from air by fractional distillation on an industrial scale.
In the lab, it can be isolated by:
- electrolysis of water with containing ions
- heating potassium chlorate with manganese dioxide,
- decomposing hydrogen peroxide with manganese dioxide
- Decomposition of hypochlorite solution (laundry bleach) using a small amount of cobalt chloride as a catalyst
- heating potassium permanganate.
A way to make liquid oxygen involves liquifying normal air with liquid nitrogen and collecting the oxygen-rich layer on top.
Handling
Safety
Atmospheric oxygen is not a hazard to health, however at high concentration it becomes dangerous to the lungs and can cause blindness. At concentrations over 50%, it will greatly amplify any exothermic reaction. Liquid oxygen is a fire and explosive hazard when in contact with organic materials and a fire source. It can also cause frostbites if it touches the skin.
Storage
Oxygen tanks and dewars should be kept in dark and cool places, away from any combustible materials. Periodically check the valves for any leaks.
Disposal
Oxygen can be safely released in open air, but never in closed places.
Gallery
Chemiluminescence of singlet oxygen
See also
References
- ↑ P. Lechtken, Chemie in unserer Zeit 1974, 8, 11-16, doi:10.1002/ciuz.19740080103
