Oxygen
Table:
Oxygen, 8O

Liquid oxygen (O2 at below −183 °C)

Oxygen
Allotropes	O2, O3 (ozone) and more (see Allotropes of oxygen)
Appearance	gas: colorless
liquid and solid: pale blue

Standard atomic weight Ar°(O)

[15.99903, 15.99977][1]
15.999±0.001 (abridged)[2]

Abundance
in the Earth's crust	461000 ppm

Oxygen in the periodic table

Hydrogen

Helium

Lithium

Beryllium

Boron

Carbon

Nitrogen

Oxygen

Fluorine

Neon

Sodium

Magnesium

Aluminium

Silicon

Phosphorus

Sulfur

Chlorine

Argon

Potassium

Calcium

Scandium

Titanium

Vanadium

Chromium

Manganese

Iron

Cobalt

Nickel

Copper

Zinc

Gallium

Germanium

Arsenic

Selenium

Bromine

Krypton

Rubidium

Strontium

Yttrium

Zirconium

Niobium

Molybdenum

Technetium

Ruthenium

Rhodium

Palladium

Silver

Cadmium

Indium

Tin

Antimony

Tellurium

Iodine

Xenon

Caesium

Barium

Lanthanum

Cerium

Praseodymium

Neodymium

Promethium

Samarium

Europium

Gadolinium

Terbium

Dysprosium

Holmium

Erbium

Thulium

Ytterbium

Lutetium

Hafnium

Tantalum

Tungsten

Rhenium

Osmium

Iridium

Platinum

Gold

Mercury (element)

Thallium

Lead

Bismuth

Polonium

Astatine

Radon

Francium

Radium

Actinium

Thorium

Protactinium

Uranium

Neptunium

Plutonium

Americium

Curium

Berkelium

Californium

Einsteinium

Fermium

Mendelevium

Nobelium

Lawrencium

Rutherfordium

Dubnium

Seaborgium

Bohrium

Hassium

Meitnerium

Darmstadtium

Roentgenium

Copernicium

Nihonium

Flerovium

Moscovium

Livermorium

Tennessine

Oganesson

–
↑
O
↓
S

nitrogen ← oxygen → fluorine

Atomic number (Z)	8
Group	group 16 (chalcogens)
Period	period 2
Block	p-block
Electron configuration	[He] 2s2 2p4
Electrons per shell	2, 6
Physical properties
Phase at STP	gas
Melting point	(O2) 54.36 K ​(−218.79 °C, ​−361.82 °F)
Boiling point	(O2) 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
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	common: −2

−1,[3] 0, +1,[3] +2[3]
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

Spectral lines of oxygen
Other properties
Natural occurrence	primordial
Crystal structure	​cubic (cP16)
Lattice constant

a = 678.28 pm (at t.p.)[4]
Thermal conductivity	26.58×10−3 W/(m⋅K)
Magnetic ordering	paramagnetic
Molar magnetic susceptibility	+3449.0×10−6 cm3/mol (293 K)[5]
Speed of sound	330 m/s (gas, at 27 °C)
CAS Number	7782-44-7
History
Naming	from the Greek ὀξύς (acid, literally 'sharp', from the taste of acids) and -γενής (producer)
Discovery	Michael Sendivogius
Carl Wilhelm Scheele (1604, 1771)
Named by	Antoine Lavoisier (1777)
Isotopes of oxygen

v
e

Main isotopes

Decay

abun­dance

half-life (t1/2)

mode

pro­duct

15O

trace

122.266 s

β+100%

15N

16O

99.8%

stable

17O

0.0380%

stable

18O

0.205%

stable

Category: Oxygen

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Based on the table, assess whether the statement is entailed, neutral, or refuted. Give your final answer in JSON format {"answer": "YOUR ANSWER"}.

Hypothesis: Oxygen was discovered at the same time it was named.

answer: neutral