Laser shots could spark additional discoveries in astrophysics

In December, the National Ignition Facility (NIF) at the U.S. Department of Energy's (DOE) Lawrence Livermore National Laboratory made headlines worldwide. Scientists at the NIF performed the first nuclear fusion experiment ...

Capturing high pressures in diamond capsules

Preservation of the high-pressure states of materials at ambient conditions is a long-sought-after goal for fundamental research and practical applications.

Argon found in air of ancient atmosphere

On the massive sheets of ice that stretch across Greenland and Antarctica, the temperature is so low that not even the summer sun can melt the snow deposited onto them. As the snow accumulates without melting and settles ...

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Argon  /ˈɑrɡɒn/ is a chemical element represented by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table (noble gases). Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide. Nearly all of this argon is radiogenic argon-40 derived from the decay of potassium-40 in the Earth's crust. In the universe, argon-36 is by far the most common argon isotope, being the preferred argon isotope produced by stellar nucleosynthesis in supernovas.

The name "argon" is derived from the Greek word αργον meaning "lazy" or "the inactive one", a reference to the fact that the element undergoes almost no chemical reactions. The complete octet (eight electrons) in the outer atomic shell makes argon stable and resistant to bonding with other elements. Its triple point temperature of 83.8058 K is a defining fixed point in the International Temperature Scale of 1990.

Argon is produced industrially by the fractional distillation of liquid air. Argon is mostly used as an inert shielding gas in welding and other high-temperature industrial processes where ordinarily non-reactive substances become reactive; for example, an argon atmosphere is used in graphite electric furnaces to prevent the graphite from burning. Argon gas also has uses in incandescent and fluorescent lighting, and other types of gas discharge tubes. Argon makes a distinctive blue-green gas laser.

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