Free Web Hosting Provider - Web Hosting - E-commerce - High Speed Internet - Free Web Page
Search the Web

   Ar

ARGON

(Gr. argos, inactive)

Ar at. wt. 39.948
   at. no. 18
   f.p. -189.2°C
   b.p. -185.7°C
   density 1.7837 gm/l
   density (liquid) 70.8 gm/l
Electronic configuration
 SHELL  K L M N O P Q
 SUB  SHELL He Neon Argon Krypton Xenon Radon Eka-radon
1s 2s 2p 3s 3p 3d 4s 4p 4d 5s 5p 4f 5d 6s 6p 5f 6d 7s 7p
Argon 1s22s22p63s23p6        
Symbol 1S0
Argon; Its presence in air was suspected by Cavendish in 1785; discovered by Lord Rayleigh and Sir William Ramsay in 1894. The gas is prepared by fractionation of liquid air, the atmosphere containing 0.94% argon. It is 24 times as soluble in water as nitrogen, having about the same solubility as oxygen; best recognized by the characteristic lines in the red end of the spectrum. It is used in electric light bulbs and in fluorescent tubes at a pressure of about 3 mm, and in filling photo tubes, glow tubes, etc. Argon is also used as an inert gas shield for arc welding and cutting, as a blanket for the production of titanium and other reactive elements, and as a protective atmosphere for growing silicon and german- ium crystals. Argon is colorless and odorless, both as a gas and liquid. It is available in high-purity form. Commercial argon is available at a cost of about 10 cents per cu. ft. Argon is considered to be a very inert gas and is not now known to form true chemical compounds, as do krypton, xenon, and radon. However, it does form a hydrate having a dissocia- lion pressure of 105 atm. at 00C. Ion molecules, such as (ArKr) +, (ArXe)+, (NeAr) +, have been observed spectro- scopically. Argon also forms a clathrate with fi hydro- quinone. This clathrate is stable and can be stored for a considerable time, but a true chemical bond does not exist. Van der Waals' forces act to hold the argon. Naturally occurring argon is a mixture of three isotopes. Five other radioactive isotopes are now known to exist.

Return to periodic table


Search For:
Match:  Any word All words Exact phrase
Sound-alike matching
Within: 
Show:   results   summaries
Sort by: 


© 1999 F. Davies
Delphi O.E.M. Co.
All rights reserved