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Technical data for Argon

Click any property name to see plots of that property for all the elements.

Overview
NameArgon
SymbolAr
Atomic Number18
Atomic Weight39.948
Density1.784 g/l[note]
Melting Point-189.3 °C
Boiling Point-185.8 °C

Thermal properties
PhaseGas
Melting Point-189.3 °C
Boiling Point-185.8 °C
Absolute Melting Point83.8 K
Absolute Boiling Point87.3 K
Critical Pressure4.898 MPa (48.34 Atm)
Critical Temperature150.87 K
Heat of Fusion1.18 kJ/mol
Heat of Vaporization6.5 kJ/mol
Heat of CombustionN/A
Specific Heat520.33 J/(kg K)[note]
Adiabatic Index5/3
Neel PointN/A
Thermal Conductivity0.01772 W/(m K)
Thermal ExpansionN/A

Bulk physical properties
Density1.784 g/l[note]
Density (Liquid)N/A
Molar Volume0.022392
Brinell HardnessN/A
Mohs HardnessN/A
Vickers HardnessN/A
Bulk ModulusN/A
Shear ModulusN/A
Young ModulusN/A
Poisson RatioN/A
Refractive Index1.000281
Speed of Sound319 m/s
Thermal Conductivity0.01772 W/(m K)
Thermal ExpansionN/A

Reactivity
Valence0
ElectronegativityN/A
ElectronAffinity0 kJ/mol
Ionization Energies
1520.6, 2665.8, 3931, 5771, 7238, 8781, 11995, 13842, 40760, 46186 kJ/mol

Health and Safety
Autoignition PointN/A
FlashpointN/A
Heat of CombustionN/A
DOT Hazard Class2.2
DOT Numbers1951
EU NumberN/A
NFPA Fire RatingN/A
NFPA HazardsN/A
NFPA Health RatingN/A
NFPA Reactivity RatingN/A
RTECS NumberRTECSCF2300000
NFPA LabelN/A

Classifications
Alternate NamesNone
Names of AllotropesNone
Blockp
Group18
Period3
Electron Configuration[Ne]3s23p6
ColorColorless
Discovery
1894 in United Kingdom
Gas phaseMonoatomic
CAS NumberCAS7440-37-1
CID NumberCID23968
Gmelin NumberN/A
NSC NumberN/A
RTECS NumberRTECSCF2300000

Electrical properties
Electrical TypeN/A
Electrical ConductivityN/A
ResistivityN/A
Superconducting PointN/A

Magnetic properties
Magnetic TypeDiamagnetic
Curie PointN/A
Mass Magnetic Susceptibility-6×10-9
Molar Magnetic Susceptibility-2.4×10-10
Volume Magnetic Susceptibility-1.07×10-8

Abundances
% in Universe0.02%
% in Sun0.007%
% in MeteoritesN/A
% in Earth's Crust0.00015%
% in Oceans0.000045%
% in HumansN/A

Atomic dimensions and structure
Atomic Radius71 pm
Covalent Radius97 pm
Van der Waals Radius188 pm
Crystal StructureFace Centered Cubic
Lattice Angles
π/2, π/2, π/2
Lattice Constants
525.6, 525.6, 525.6 pm
Space Group NameFm_ 3m
Space Group Number225

Nuclear Properties
Half-LifeStable
LifetimeStable
Decay ModeN/A
Quantum Numbers1S0
Neutron Cross Section0.65
Neutron Mass Absorption0.0006
Known Isotopes
30Ar, 31Ar, 32Ar, 33Ar, 34Ar, 35Ar, 36Ar, 37Ar, 38Ar, 39Ar, 40Ar, 41Ar, 42Ar, 43Ar, 44Ar, 45Ar, 46Ar, 47Ar, 48Ar, 49Ar, 50Ar, 51Ar, 52Ar, 53Ar
Stable Isotopes
36Ar, 38Ar, 40Ar
Isotopic Abundances
36Ar0.3365%
38Ar0.0632%
40Ar99.6003%


Notes on the properties of Argon:

Density: Density at 0° Celsius.

Specific Heat: Value given for gas phase.

Up to date, curated data provided by
Mathematica's ElementData function from Wolfram Research, Inc.

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