Mineral Species containing Argon (Ar)

**Argon (Ar) Element Properties**
Atomic Mass	39.948
Atomic Number	18
Name Origins	Greek, argos = "Inactive" - In allusion to the complete lack of any chemical affinity to any element
Year Discovered	1894
Discovery Credits	Discovered by Lord Reyleigh (London) and Sir William Ramsay (Bristol) in the United Kingdom.
Remarks	Colorless, odorless gas that comprises about 1% of Earth's planetary atmosphere. Argon is present in miniscule amounts in potassium-bearing minerals where radioactive K⁴⁰ decays to AR⁴⁰. This argon is trapped in the crystal lattice of the mineral and is easily expelled by heating the mineral and collecting the gas. The gas is purified and is spiked with an isotopic tracer and measured using a mass-spectrometer to derive the age of the mineral. The lower limit of age-dating using the K-Ar method is about 10,000 years for a releatively potassum-rich mineral. The upper age limit is billions of years. Used as an inert atmosphere in lamps and high temperature metallurgy.
References	Emsley, J., 1991; THE ELEMENTS : Sec. Ed., Clarendon Press, Oxford, 251 p.
See Also	WebElements, ChemiCool

Atomic Mass

39.948

Atomic Number

18

Name Origins

Greek, argos = "Inactive" - In allusion to the complete lack of any chemical affinity to any element

Year Discovered

1894

Discovery Credits

Discovered by Lord Reyleigh (London) and Sir William Ramsay (Bristol) in the United Kingdom.

Remarks

Colorless, odorless gas that comprises about 1% of Earth's planetary atmosphere.

Argon is present in miniscule amounts in potassium-bearing minerals where radioactive K⁴⁰ decays to AR⁴⁰. This argon is trapped in the crystal lattice of the mineral and is easily expelled by heating the mineral and collecting the gas. The gas is purified and is spiked with an isotopic tracer and measured using a mass-spectrometer to derive the age of the mineral. The lower limit of age-dating using the K-Ar method is about 10,000 years for a releatively potassum-rich mineral. The upper age limit is billions of years.

Used as an inert atmosphere in lamps and high temperature metallurgy.

References

Emsley, J., 1991; THE ELEMENTS : Sec. Ed., Clarendon Press, Oxford, 251 p.

Symbol	Isotope Mass	Isotope Nuclide Number	Isotope Number	Natural Abundance	Half-life	Half-life Units	Decay Mode	Decay Mode MeV	Decay Mode %
Ar	35.967545	36	18	0.337%		Stable
Ar	36.966776	37	18	0	34.8	days	EC	0.814	100.00
Ar	37.962732	38	18	0.063%		stable
Ar	38.962314	39	18	0	269	years	β-	3.44	100.00
Ar	39.962384	40	18	99.60%		stable

There are no minerals containing Argon (Ar)