Argon (Ar)

chemical element with symbol Ar and atomic number 18; rare gas

Atomic Number	18
Atomic Weight	39.948
mass number	40

Group	18
Period	3
Block	p

proton	18 p⁺
neutron	22 n⁰
electron	18 e^-

Physical Property

Atomic Radius	71 pm 197 pm
molar volume	24.2 cm³/mol
covalent radius	96 pm 107 pm 96 pm 106 pm
Metallic Radius
ionic radius
Crystal Radius
Van der Waals radius	188 pm 188 pm 199 pm 386.8 pm
dosedh	0.001633 g/cm³

Chemical Property

nerth

proton affinity	369.2 kJ/mol
electron affinity	-11.5 eV/particle
ionization energy	15.7596112 eV/particle 27.62967 eV/particle 40.735 eV/particle 59.58 eV/particle 74.84 eV/particle 91.29 eV/particle 124.412 eV/particle 143.4567 eV/particle 422.598 eV/particle 479.76 eV/particle 540.43 eV/particle 618.95 eV/particle 685.47 eV/particle 755.13 eV/particle 855.47 eV/particle 918.374 eV/particle 4,120.6655 eV/particle 4,426.2227 eV/particle

enthalpy of vaporization	6.52 kJ/mol
enthalpy of fusion
standard enthalpy of formation
electron

electron shell	2, 8, 8

valence electron	8 ⓘ

aray an elektrons	[Ne] 3s² 3p⁶ⓘ 1s² 2s² 2p⁶ 3s² 3p⁶

oxidation number	0
electronegativity	19.17 eV/particle 0.2922
Electrophilicity Index	0.0832013314590371 eV/particle
fundamental state of matter

phase of matter	Gas
gaseous state of matter	Monoatomic
Boiling Point	87.302 K
Melting Point	83.81 K
critical pressure	4.863 MPa
critical temperature	150.687 K
triple point	83.8058 K 68.89 kPa
appearance
liw	Colorless #ff1493 #80d1e3 #80d1e3
appearance	colorless gas exhibiting a lilac/violet glow when placed in a high voltage electric field
refractive index	1.000281
thermodynamic material property
Thermal Conductivity	0.0177 W/(m K)
thermal expansion
molar heat capacity	20.786 J/(mol K)
Specific Heat Capacity	0.52 J/(g⋅K)
heat capacity ratio	5/3
electrical properties
type
electrical conductivity
electrical resistivity
superconductivity
magnetism
type	diamagnetic
magnetic susceptibility (Mass)	-0.000000006 m³/Kg
magnetic susceptibility (Molar)	-0.00000000024 m³/mol
magnetic susceptibility (Volume)	-0.0000000107
magnetic ordering
Curie temperature
Néel temperature
kesweyth
Crystal Structure	Face Centered Cubic (FCC)
lattice constant	5.26 Å
Lattice Angles	π/2, π/2, π/2
mechanical property
hardness
bulk modulus
shear modulus
Young's modulus
Poisson's ratio
speed of sound	319 m/s
classification
Category	Noble gases, Noble gases
CAS Group	VIII
IUPAC Group	VIIIA
Glawe Number	3
Mendeleev Number	114
Pettifor Number	3
Geochemical Class	volatile
Goldschmidt classification	atmophile

other

Gas Basicity	346.3 kJ/mol
polarizability	11.083 ± 0.007 a₀
C6 Dispersion Coefficient	64.2 a₀ 67.4 a₀
allotrope
Neutron cross section	0.66
Neutron Mass Absorption	0.00059
quantum number	1S0
space group	225 (Fm_3m)

Isotopes of Argon

Stable Isotopes	2
Unstable Isotopes	24
Natural Isotopes	3

²⁹Ar

mass number	29
neutron number	11
relative atomic mass	29.040761 ± 0.000471 Da
g-factor
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life
spin	5/2
nuclear quadrupole moment
dydhyas diskudhans	2018
parity	+

decay mode	intensity
2p (2-proton emission)	100%

³⁰Ar

mass number	30
neutron number	12
relative atomic mass	30.023694 ± 0.000192 Da
g-factor	0
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life
spin	0
nuclear quadrupole moment	0
dydhyas diskudhans	2015
parity	+

decay mode	intensity
2p (2-proton emission)	100%

³¹Ar

mass number	31
neutron number	13
relative atomic mass	31.012158 ± 0.000215 Da
g-factor
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	15 ± 0.3 ms
spin	5/2
nuclear quadrupole moment
dydhyas diskudhans	1986
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ p (β⁺-delayed proton emission)	68.3%
2p (2-proton emission)	9%
B+pA	0.38%
3p	0.07%
β⁺α (β⁺-delayed α emission)	0.03%
2p (2-proton emission)	0.0006%

³²Ar

mass number	32
neutron number	14
relative atomic mass	31.997637824 ± 0.0000019 Da
g-factor	0
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	98 ± 2 ms
spin	0
nuclear quadrupole moment	0
dydhyas diskudhans	1977
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ p (β⁺-delayed proton emission)	35.58%

³³Ar

mass number	33
neutron number	15
relative atomic mass	32.989925545 ± 0.00000043 Da
g-factor	-1.446 ± 0.012
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	173 ± 2 ms
spin	1/2
nuclear quadrupole moment	0
dydhyas diskudhans	1964
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ p (β⁺-delayed proton emission)	38.7%

³⁴Ar

mass number	34
neutron number	16
relative atomic mass	33.980270092 ± 0.000000083 Da
g-factor	0
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	846.46 ± 0.35 ms
spin	0
nuclear quadrupole moment	0
dydhyas diskudhans	1966
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%

³⁵Ar

mass number	35
neutron number	17
relative atomic mass	34.975257719 ± 0.00000073 Da
g-factor	0.42133333333333 ± 0.00013333333333333
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	1.7756 ± 0.001 s
spin	3/2
nuclear quadrupole moment	-0.084 ± 0.015
dydhyas diskudhans	1940
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%

³⁶Ar

mass number	36
neutron number	18
relative atomic mass	35.967545106 ± 0.000000028 Da
g-factor	0
natural abundance	0.3336 ± 0.021
radioactivity	☢️ elven radyoweythresek
half-life
spin	0
nuclear quadrupole moment	0
dydhyas diskudhans	1920
parity	+

decay mode	intensity
2β⁺ (double β⁺ decay)

³⁷Ar

mass number	37
neutron number	19
relative atomic mass	36.966776301 ± 0.000000221 Da
g-factor
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	35.011 ± 0.019 d
spin	3/2
nuclear quadrupole moment	0.076 ± 0.003
dydhyas diskudhans	1941
parity	+

decay mode	intensity
ϵ (electron capture)	100%

³⁸Ar

mass number	38
neutron number	20
relative atomic mass	37.962732102 ± 0.000000209 Da
g-factor	0
natural abundance	0.0629 ± 0.007
radioactivity	stable isotope
half-life	Not Radioactive ☢️
spin	0
nuclear quadrupole moment	0
dydhyas diskudhans	1934
parity	+

³⁹Ar

mass number	39
neutron number	21
relative atomic mass	38.964313037 ± 0.000005367 Da
g-factor	-0.45428571428571 ± 0.0042857142857143
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	268 ± 8 y
spin	7/2
nuclear quadrupole moment	-0.116 ± 0.002
dydhyas diskudhans	1950
parity	-

decay mode	intensity
β⁻ (β⁻ decay)	100%

⁴⁰Ar

mass number	40
neutron number	22
relative atomic mass	39.96238312204 ± 0.00000000234 Da
g-factor	0
natural abundance	99.6035 ± 0.025
radioactivity	stable isotope
half-life	Not Radioactive ☢️
spin	0
nuclear quadrupole moment	0
dydhyas diskudhans	1920
parity	+

⁴¹Ar

mass number	41
neutron number	23
relative atomic mass	40.96450057 ± 0.000000372 Da
g-factor	-0.37428571428571 ± 0.0022857142857143
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	109.61 ± 0.04 m
spin	7/2
nuclear quadrupole moment	-0.042 ± 0.004
dydhyas diskudhans	1936
parity	-

decay mode	intensity
β⁻ (β⁻ decay)	100%

⁴²Ar

mass number	42
neutron number	24
relative atomic mass	41.963045737 ± 0.0000062 Da
g-factor	0
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	32.9 ± 1.1 y
spin	0
nuclear quadrupole moment	0
dydhyas diskudhans	1952
parity	+

decay mode	intensity
β⁻ (β⁻ decay)	100%

⁴³Ar

mass number	43
neutron number	25
relative atomic mass	42.965636056 ± 0.0000057 Da
g-factor	-0.4088 ± 0.0024
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	5.37 ± 0.06 m
spin	5/2
nuclear quadrupole moment	0.142 ± 0.014
dydhyas diskudhans	1969
parity

decay mode	intensity
β⁻ (β⁻ decay)	100%

⁴⁴Ar

mass number	44
neutron number	26
relative atomic mass	43.964923814 ± 0.0000017 Da
g-factor	0
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	11.87 ± 0.05 m
spin	0
nuclear quadrupole moment	0
dydhyas diskudhans	1969
parity	+

decay mode	intensity
β⁻ (β⁻ decay)	100%

⁴⁵Ar

mass number	45
neutron number	27
relative atomic mass	44.968039731 ± 0.00000055 Da
g-factor
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	21.48 ± 0.15 s
spin	5/2
nuclear quadrupole moment
dydhyas diskudhans	1974
parity	-

decay mode	intensity
β⁻ (β⁻ decay)	100%

⁴⁶Ar

mass number	46
neutron number	28
relative atomic mass	45.968039244 ± 0.0000025 Da
g-factor	0
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	8.4 ± 0.6 s
spin	0
nuclear quadrupole moment	0
dydhyas diskudhans	1974
parity	+

decay mode	intensity
β⁻ (β⁻ decay)	100%

⁴⁷Ar

mass number	47
neutron number	29
relative atomic mass	46.972767112 ± 0.0000013 Da
g-factor
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	1.23 ± 0.03 s
spin	3/2
nuclear quadrupole moment
dydhyas diskudhans	1985
parity

decay mode	intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	0.2%

⁴⁸Ar

mass number	48
neutron number	30
relative atomic mass	47.976001 ± 0.000018 Da
g-factor	0
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	415 ± 15 ms
spin	0
nuclear quadrupole moment	0
dydhyas diskudhans	2004
parity	+

decay mode	intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	38%

⁴⁹Ar

mass number	49
neutron number	31
relative atomic mass	48.981685 ± 0.000429 Da
g-factor
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	236 ± 8 ms
spin	3/2
nuclear quadrupole moment
dydhyas diskudhans	1989
parity	-

decay mode	intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	29%
2n (2-neutron emission)

⁵⁰Ar

mass number	50
neutron number	32
relative atomic mass	49.985797 ± 0.000537 Da
g-factor	0
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life	106 ± 6 ms
spin	0
nuclear quadrupole moment	0
dydhyas diskudhans	1989
parity	+

decay mode	intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	37%
2n (2-neutron emission)

⁵¹Ar

mass number	51
neutron number	33
relative atomic mass	50.993033 ± 0.000429 Da
g-factor
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life
spin	1/2
nuclear quadrupole moment	0
dydhyas diskudhans	1989
parity	-

decay mode	intensity
β⁻ (β⁻ decay)
β⁻ n (β⁻-delayed neutron emission)
2n (2-neutron emission)

⁵²Ar

mass number	52
neutron number	34
relative atomic mass	51.998519 ± 0.000644 Da
g-factor	0
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life
spin	0
nuclear quadrupole moment	0
dydhyas diskudhans	2009
parity	+

decay mode	intensity
β⁻ (β⁻ decay)
β⁻ n (β⁻-delayed neutron emission)
2n (2-neutron emission)

⁵³Ar

mass number	53
neutron number	35
relative atomic mass	53.00729 ± 0.00075 Da
g-factor
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life
spin	5/2
nuclear quadrupole moment
dydhyas diskudhans	2009
parity	-

decay mode	intensity
β⁻ (β⁻ decay)
β⁻ n (β⁻-delayed neutron emission)
2n (2-neutron emission)

⁵⁴Ar

mass number	54
neutron number	36
relative atomic mass	54.013484 ± 0.000859 Da
g-factor	0
natural abundance
radioactivity	☢️ elven radyoweythresek
half-life
spin	0
nuclear quadrupole moment	0
dydhyas diskudhans	2018
parity	+

decay mode	intensity
β⁻ (β⁻ decay)
β⁻ n (β⁻-delayed neutron emission)
2n (2-neutron emission)

istori

diskudher po dismyger	Sir William Ramsey, Baron Rayleigh
location of discovery	Scotland
dydhyas diskudhans	1894
Etymologyl	Greek: argos (inactive).
pronunciation	AR-gon (en)

source

Abundance
Abundance in Earth's crust	3.5 mg/kg
natural abundance (Keynvor)	0.45 mg/L
natural abundance (Korf)
natural abundance (meteoroid)
natural abundance (Howl)	0.007 %
Abundance in Universe	0.02 %

Nuclear Screening Constants

1	s	0.4925
2	p	3.9918
2	s	5.7696
3	p	11.2359
3	s	10.2432

Argon on ChemicalAid

Art & Architecture Thesaurus ID	300133261
Australian Educational Vocabulary ID	scot/1608
BNCF Thesaurus ID	30962
Bibliothèque nationale de France ID	119700051
Brockhaus Enzyklopädie online ID	argon
CAB ID	42654
CAS Registry Number	7440-37-1
ChEBI ID	49475
ChemSpider ID	22407
CosIng number	54501
DSSTOX compound identifier	DTXCID0031055
DSSTox substance ID	DTXSID3052482
Den Store Danske ID	argon
ECHA Substance Infocard ID	100.028.315
Encyclopædia Universalis ID	argon
E number	E938
Freebase ID	/m/027r9df
French Vikidia ID	Argon
Gran Enciclopèdia Catalana ID	0004615
Great Russian Encyclopedia Online ID	1827507
Gujarati Vishwakosh entry	આગૉર્ન
HSDB ID	7902
ICSC ID	0154
InChI	InChI=1S/Ar
InChIKey	XKRFYHLGVUSROY-UHFFFAOYSA-N
KBpedia ID	Argon
Latvian National Encyclopedia Online ID	133180
Library of Congress authority ID	sh85007108
MeSH descriptor ID	D001128
NDL Authority ID	00575518
National Library of Israel J9U ID	987007295519905171
National Library of Latvia ID	000328279
OmegaWiki Defined Meaning	15591
OpenAlex ID	C547737533
OpenAlex ID	C2992172976
Open Food Facts ingredient ID	propellent-gas-e938
PDB ligand ID	AR
PDB structure ID	1C6F
PDB structure ID	1C6I
PDB structure ID	1C66
PDB structure ID	1C6C
PSH ID	5818
PubChem CID	23968
Quora topic ID	Argon-element
RxNorm ID	1368133
Römpp online ID	RD-01-03226
Spanish Vikidia ID	Argón
Store norske leksikon ID	argon
Treccani Vocabulary ID	argon
U.S. National Archives Identifier	10639898
UK Archival Thesaurus ID	f2/mt225/4347/12165
UNII	67XQY1V3KH
USGS Thesaurus ID	1395
WordNet 3.1 Synset ID	14653098-n
YSO ID	14683
ZVG number	7180
honanieth GND	4142990-4

Argon (Ar)

Physical Property

Chemical Property

other

Isotopes of Argon

29Ar

30Ar

31Ar

32Ar

33Ar

34Ar

35Ar

36Ar

37Ar

38Ar

39Ar

40Ar

41Ar

42Ar

43Ar

44Ar

45Ar

46Ar

47Ar

48Ar

49Ar

50Ar

51Ar

52Ar

53Ar

54Ar

istori

source

Nuclear Screening Constants

²⁹Ar

³⁰Ar

³¹Ar

³²Ar

³³Ar

³⁴Ar

³⁵Ar

³⁶Ar

³⁷Ar

³⁸Ar

³⁹Ar

⁴⁰Ar

⁴¹Ar

⁴²Ar

⁴³Ar

⁴⁴Ar

⁴⁵Ar

⁴⁶Ar

⁴⁷Ar

⁴⁸Ar

⁴⁹Ar

⁵⁰Ar

⁵¹Ar

⁵²Ar

⁵³Ar

⁵⁴Ar