ARGON, Ar (18)

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ARGON

Ar (18)

ˈɑːɡɒn

PHONETICS

Argon is the third most common gas with 0.93% of the Earth’s atmosphere. Almost all argon is radiogenic argon-40, derived from the decay of potassium-40 in the Earth’s crust.

ELEMENT BRIEF

1894 by Sir William Ramsay and Lord Rayleigh, London, England.

DISCOVERY

Ancient Greek, ἀργόν (argón), neuter of ἀργός (argós, 'idle, lazy').

ETYMOLOGY

Argon

ELEMENT

Ar

SYMBOL

18

ATOMIC NUMBER

7440-37-1

CAS NUMBER
element

ELEMENTAL SPECTRUM


Colourless

ELEMENTAL COLOUR


1.000'281

REFRACTIVE INDEX


-

POISSON RATIO


-

MOLAR VOLUME


-

BRINELL HARDNESS


-

MOHS HARDNESS


-

VICKERS HARDNESS


319 m/s, Mach 0.930'0

SPEED OF SOUND


-

BULK MODULUS


-

SHEAR MODULUS


-

YOUNG MODULUS


ALLOTROPES

element element

83.85 K, -189.30 °C

MELTING POINT


87.35 K, -185.80 °C

BOILING POINT


-

AUTOMATIC IGNITION


-

FLASHPOINT


150.87 K, -122.28 °C

CRITICAL TEMPERATURE


4.90M Pa, 48 Atm

CRITICAL PRESSURE


0.017'720 W/(m K)

THERMAL CONDUCTIVITY


-

THERMAL EXPANSION


520.33 J/(kg K)

SPECIFIC HEAT


1.180 kJ/mol

HEAT FUSION


6.500 kJ/mol

HEAT VAPORISATION


-

HEAT COMBUSTION


-

CURIE POINT


-

NEEL POINT


5/3

ADIABATIC INDEX


Gas

PHASE

-

ELECTRICAL TYPE


-

CONDUCTIVITY


-

RESISTIVITY


-

SUPERCONDUCTING POINT


Diamagnetic

MAGNETIC TYPE


-0.000'000'006'0

MASS SUSCEPTIBILITY


-0.000'000'000'240'00

MOLAR SUSCEPTIBILITY


-0.000'000'010'70

VOLUME SUSCEPTIBILITY

Noble Gas

CLASSIFICATION


39.947'676'7

ATOMIC WEIGHT


71 pm

ATOMIC RADIUS


96 pm

COVALENT RADIUS SINGLE BOND


107 pm

COVALENT RADIUS DOUBLE BOND


96 pm

COVALENT RADIUS TRIPLE BOND


188 pm

VAN DER WAALS RADIUS


[Ne]3s²3P⁶

ELECTRON CONFIGURATION


Cubic, Face-centred

CRYSTAL STRUCTURE


-

DENSITY AS SOLID


-

DENSITY AS LIQUID


1.784'00 g/cm³

DENSITY AS GAS


Fm_3m

SPACE GROUP NAME


225

SPACE GROUP NUMBER


π/2, π/2 π/2

LATTICE ANGLES


525.6, 525.6 525.6 pm

LATTICE CONSTANTS

0

VALENCE


-

ELECTRONEGATIVITY


-96.49 kJ/mol

ELECTRON AFFINITY


IONISATION ENERGY

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0.02 %

UNIVERSE


-

METEORITES


0.007 %

SUN


0.000'15 %

EARTH CRUST


0.000'045 %

OCEANS


-

HUMANS

Stable

HALF LIFE


Stable

LIFETIME


3p⁶ = 3, 1, +1, -1/2

QUANTUM NUMBERS


0.683'00 b σs

NEUTRON CROSS SECTION


0.675'00 b σa

NEUTRON MASS ABSORPTION


STABLE ISOTOPES

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UNSTABLE ISOTOPES

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ISOTOPIC CHAIN

CENTRALDATACORE

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