The planet where Superman was born. The planet exploded soon after Superman's birth and he was one of very few survivors. The substance kryptonite comes from the remnants of the planet and is a serious threat to Superman's powers.

An element discovered by the English chemists Sir William Ramsay and Morris Travers in 1898, using fractional distillation. It is one of the noble gasses. Its symbol is Kr, and its atomic number is 36.

He took the name from the Greek word kryptos, meaning hidden.

Its main use in is neon lights, in which it is used to make a pale violet. It is also often used for airport runway lights. Since it also has a fast response time to electric currents, it is often used with xenon in high-intensity, sort-exposure photographic flash bulbs and in strobe lights.

In 1960 an international committee decided to use the wavelength of one of the colors of krypton-86 to define the meter. A meter was exactly 1,650,762.73 wavelengths of the red-orange spectral line of krypton-86. The meter has since been redefined as 1/299,792,458 of the distance light (in a vacuum) travels in a second.

(So named (Greek krypton, "hidden") in 1898 by Sir William Ramsay and M. W. Travers, British chemist, its discoverers, in reference to their difficulty in isolating it) A rare, gaseous chemical element, one of the noble gases, present in very small quantities in air. It is basically inert, but reacts with fluorine and some other elements under special conditions.

Symbol: Kr
Atomic number: 36
Atomic weight: 83.80
Density (at 0°C with 101,325 pascals): 3.7 g/L
Melting point: -156.6°C
Boiling point: -152.3°C
Valence: 0
Ground state electron configuration: [Ar]3d104s24p6

Symbol: Kr
Atomic Number: 36
Atomic Weight: 83.80
Boiling Point: 120.85 K
Melting Point: 116 K
Density at 300K: 3.75 g/cm3
Covalent radius: 1.89
Atomic radius: 1.03
Atomic volume: 32.2 cm3/mol
First ionization potental: 13.999 V
Specific heat capacity: 0.248 J g-1 K-1
Thermal conductivity: 0.00949 W m-1 K-1
Electrical conductivity: N/A
Heat of fusion: 1.638 kJ/mol
Heat of vaporization: 9.029 kJ/mol
Electronegativity: N/A

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Kryp"ton (?), n. [NL., fr. Gr. &?; , neut. of &?; hidden.] (Chem.)

An inert gaseous element of the argon group, occurring in air to the extent of about one volume in a million. It was discovered by Ramsay and Travers in 1898. Liquefying point, -- 152° C.; symbol, Kr; atomic weight, 83.0.


© Webster 1913.

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