VisualChem The interactive chemistry textbook
中文
8 O Oxygen 15.999

Nonmetal

Oxygen 氧

[He] 2s² 2p⁴

  • Period 2
  • Group 16
  • Block p
  • Gas

Electron configuration

1s² 2s² 2p⁴

Orbital diagram (valence)

2s ↑↓
2p ↑↓↑↑
Electrons per shell
2, 6
Unpaired electrons
2
Zeff (Slater)
4.55

Properties

Atomic weight
15.999
Electronegativity (Pauling)
3.44
First ionization energy
1314 kJ/mol
Electron affinity
141 kJ/mol
Covalent radius
66 pm
van der Waals radius
152 pm
Melting point
54.36 K
Boiling point
90.2 K
Density
0.001429 g/cm³
Melting / boiling point
−218.8 °C / −182.9 °C
Common oxidation states
−2
Discovered
1774

Natural isotopes

161718m/z020406080100Abundance / %
Mass number AAtomic mass / uAbundance
16O15.99491599.76 %
17O16.9991320.0380 %
18O17.9991600.2050 %

Isotope masses: AME2020; abundances: IUPAC/CIAAW representative values.

Successive ionization energies

1: 13.62 eV2: 35.12 eV3: 54.94 eV4: 77.41 eV5: 113.90 eV6: 138.12 eV7: 739.33 eV8: 871.41 eV12345678n-th electron removed101001000Ionization energy / eV (log)

The big jumps appear where core electrons start to be removed. Ionization energies from the NIST Atomic Spectra Database.

Oxygen in the course

The lessons that discuss this element most (ranked by mentions).

Lab experiments with Oxygen

Standard reduction potentials

OX3(g)+2 HX+(aq)+2 eX−→OX2(g)+HX2O(l)\ce{O3(g)} + \ce{2H+(aq)} + \ce{2e-} \mathrel{\ce{->}} \ce{O2(g)} + \ce{H2O(l)}+2.076 V
HX2OX2(aq)+2 HX+(aq)+2 eX−→2 HX2O(l)\ce{H2O2(aq)} + \ce{2H+(aq)} + \ce{2e-} \mathrel{\ce{->}} \ce{2H2O(l)}+1.776 V
OX2(g)+4 HX+(aq)+4 eX−→2 HX2O(l)\ce{O2(g)} + \ce{4H+(aq)} + \ce{4e-} \mathrel{\ce{->}} \ce{2H2O(l)}+1.229 V
OX2(g)+2 HX+(aq)+2 eX−→HX2OX2(aq)\ce{O2(g)} + \ce{2H+(aq)} + \ce{2e-} \mathrel{\ce{->}} \ce{H2O2(aq)}+0.695 V
OX2(g)+2 HX2O(l)+4 eX−→4 OHX−(aq)\ce{O2(g)} + \ce{2H2O(l)} + \ce{4e-} \mathrel{\ce{->}} \ce{4OH-(aq)}+0.401 V
OX2(g)+HX2O(l)+2 eX−→HOX2X−(aq)+OHX−(aq)\ce{O2(g)} + \ce{H2O(l)} + \ce{2e-} \mathrel{\ce{->}} \ce{HO2-(aq)} + \ce{OH-(aq)}−0.076 V
All potentials

Crystal structures

  • ZnO\ce{ZnO} Wurtzite lattice parameter a = 325.0 pm
  • TiOX2\ce{TiO2} Rutile lattice parameter a = 459.4 pm
  • SrTiOX3\ce{SrTiO3} Perovskite lattice parameter a = 390.5 pm
View in the crystal atlas

Periodic trend

H: 1312 kJ/molHe: 2372 kJ/molLi: 520.2 kJ/molBe: 899.5 kJ/molB: 800.6 kJ/molC: 1086 kJ/molN: 1402 kJ/molO: 1314 kJ/molF: 1681 kJ/molNe: 2081 kJ/molNa: 495.8 kJ/molMg: 737.7 kJ/molAl: 577.6 kJ/molSi: 786.5 kJ/molP: 1012 kJ/molS: 999.6 kJ/molCl: 1251 kJ/molAr: 1521 kJ/molK: 418.8 kJ/molCa: 589.8 kJ/molSc: 633 kJ/molTi: 658.8 kJ/molV: 650.9 kJ/molCr: 652.9 kJ/molMn: 717.3 kJ/molFe: 762.4 kJ/molCo: 760.4 kJ/molNi: 737.1 kJ/molCu: 745.4 kJ/molZn: 906.4 kJ/molGa: 578.8 kJ/molGe: 762.2 kJ/molAs: 947 kJ/molSe: 940.9 kJ/molBr: 1140 kJ/molKr: 1351 kJ/molRb: 403 kJ/molSr: 549.5 kJ/molY: 599.8 kJ/molZr: 640.1 kJ/molNb: 652.1 kJ/molMo: 684.3 kJ/molTc: 702.4 kJ/molRu: 710.2 kJ/molRh: 719.7 kJ/molPd: 804.4 kJ/molAg: 731 kJ/molCd: 867.8 kJ/molIn: 558.3 kJ/molSn: 708.6 kJ/molSb: 833.6 kJ/molTe: 869.3 kJ/molI: 1008 kJ/molXe: 1170 kJ/molCs: 375.7 kJ/molBa: 502.9 kJ/mol 0510152025303540455055Atomic number Z05001000150020002500First ionization energy / kJ/mol

Group 16

Data: PubChem periodic table (public domain); atomic weights are IUPAC abridged standard values; covalent radii from Cordero et al. (2008).