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oxygen
Image: Wikimedia Commons

oxygen

Chemical element with symbol O and atomic number 8

Chemical elementchemical elementlithophile elementQ629

Also known as E948 · element 8

Symbol
Atomic number
Mass
Melting point
  • 54.8 K
Boiling point
  • 90.15 K
Density
  • 1,804.13 kg/m³
Discovered by
Discovered
  • 1774
  • , 1771

Overview

All data

176 statements · 18% with external sources · numbers in brackets are citations

Oxidation state
  • -2
  • -1
  • 1
  • 2
  • 0
Electronegativity
Permanent duplicated item
Location of discovery
Opposite of
Named after
Unicode character
Radius
Electron configuration
  • [He] 2s² 2p⁴
  • 1s² 2s² 2p⁴
Ionization energy
  • 1,313.9 kilojoule per mole
  • 3,388.3 kilojoule per mole
  • 5,300.5 kilojoule per mole
  • 7,469.2 kilojoule per mole
Has characteristic
Different from
Part of
Subclass of
Has use
Members / parts
Ionic radius
  • 142 picometre charge number: -2 · coordination number: 8
  • 1.21 ångström coordination number: 2 · charge number: -2
  • 1.4 ångström charge number: -2 · coordination number: 6
Frequency
Formula
  • O
Thermal conductivity
  • 0.02658 watt per metre kelvin
Specific heat capacity
  • 920 joule per kilogram kelvin
Speed of sound
  • 317.5 m/s
Standard enthalpy of formation
  • 249.18 kilojoule per mole state of matter: gas
Standard molar entropy
  • 161.059 joule per mole kelvin state of matter: gas
Crystal system
Van der Waals radius
  • 152 picometre
Atomic radius
  • 60 picometre
Covalent radius
  • 66 picometre

On other databases

95 identifiers linking oxygen across the web's reference databases