Template:Infobox oxygen

Oxygen,  ₈O

Spectral lines of oxygen
General properties
Name, symbol	oxygen, O
Appearance	gas: colorless liquid: pale blue
Pronunciation	/ˈɒksᵻdʒən/ OK-si-jən
Oxygen in the periodic table
– ↑ O ↓ S nitrogen ← oxygen → fluorine
Atomic number (Z)	8
Group, block	group 16 (chalcogens), p-block
Period	period 2
Element category	diatomic nonmetal
Standard atomic weight (Ar)	15.999 (15.99903–15.99977)
Electron configuration	[He] 2s2 2p4
per shell	2, 6
Physical properties
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 stp (0 °C and 101.325 kPa)	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
Heat of vaporization	(O2) 6.82 kJ/mol
Molar heat capacity	(O2) 29.378 J/(mol·K)
vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K)       61 73 90
Atomic properties
Oxidation states	2, 1, −1, −2
Electronegativity	Pauling scale: 3.44
Ionization 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
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 Number	7782-44-7
History
Discovery	Carl Wilhelm Scheele (1772)
Named by	Antoine Lavoisier (1777)
Most stable isotopes of oxygen
iso NA half-life DM DE (MeV) DP 16O 99.76% 16O is stable with 8 neutrons 17O 0.039% 17O is stable with 9 neutrons 18O 0.201% 18O is stable with 10 neutrons

References

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