Template:Infobox oxygen

Oxygen,  ₈O

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General properties
Pronunciation	Template:Infobox element/pronunciation
Allotropes	O2, O3 (Ozone)
Appearance	gas: colorless liquid: pale blue
Standard atomic weight (Ar, standard)	Template:Infobox element/standard atomic weight
Mass number	Template:Infobox element/symbol-to-most-stable-isotope (most stable isotope)
Oxygen in the periodic table
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Atomic number (Z)	8
Group	Template:Infobox element/group
Period	period 2
Block	p-block
Element category	Template:Infobox element/category format
Electron configuration	[He] 2s2 2p4
Electrons per shell	2, 6
Physical properties
Phase at STP	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 STP)	1.429 g/L
when liquid (at b.p.)	1.141 g/cm3
Triple point	54.361 K, ​0.1463 kPa
Critical point	154.581 K, 5.043 MPa
Heat of fusion	(O2) 0.444 kJ/mol
[[Enthalpy of vaporization|Heat of Template:Engvar]]	(O2) 6.82 kJ/mol
Molar heat capacity	(O2) 29.378 J/(mol·K)
[[Vapor pressure|Template:Engvar pressure]] Template:Infobox element/vapor pressure table
Atomic properties
Oxidation states	Template:Infobox element/symbol-to-oxidation-state
Electronegativity	Pauling scale: 3.44
[[Ionization energy|Template:Engvar energies]]	1st: 1313.9 kJ/mol 2nd: 3388.3 kJ/mol 3rd: 5300.5 kJ/mol (more)
Covalent radius	66±2 pm
Van der Waals radius	152 pm
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Other properties
Crystal structure	​Template:Infobox element/crystal structure Template:Infobox element/crystal structure
Speed of sound	330 m/s (gas, at 27 °C)
Thermal conductivity	26.58×10−3  W/(m·K)
Magnetic ordering	paramagnetic
Magnetic susceptibility	+3449.0·10−6 cm3/mol (293 K)
CAS Number	7782-44-7
History
Discovery	Carl Wilhelm Scheele (1771)
Named by	Antoine Lavoisier (1777)
Main isotopes of oxygen
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