Technical data for Argon

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 Presure4.898 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
Thermal Conductivity0.01772 W/(m K)
Thermal ExpansionN/A

Bulk physical properties
Density1.784 g/l[note]
Density (Liquid)N/A
Molar Volume0.022392
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

Classifications
Alternate NamesNone
Nams of AllotropesNone
Blockp
Group18
Period3
Electron Configuration[Ne]3s23p6
ColorColorless
Discovery
1894 in United Kingdom
Gas phaseMonoatomic
CAS NumberCAS7440-37-1

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
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.