Krypton Facts

Krypton Chemical & Physical Properties

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Krypton Basic Facts

Atomic Number: 36

Symbol: Kr

Atomic Weight: 83.80

Discovery: Sir William Ramsey, M.W. Travers, 1898 (Great Britain)

Electron Configuration: [Ar] 4s2 3d10 4p6

Word Origin: Greek kryptos: hidden

Isotopes: There are 30 known isotopes of krypton ranging from Kr-69 to Kr-100. There are 6 stable isotopes: Kr-78 (0.35% abundance), Kr-80 (2.28% abundance), Kr-82 (11.58% abundance), Kr-83 (11.49% abundance), Kr-84 (57.00% abundance), and Kr-86 (17.30% abundance).

Element Classification: Inert Gas

Density: 3.09 g/cm3 (@4K - solid phase)
2.155 g/mL (@-153°C - liquid phase)
3.425 g/L (@25°C and 1 atm - gas phase)

Krypton Physical Data

Melting Point (K): 116.6

Boiling Point (K): 120.85

Appearance: dense, colorless, odorless, tasteless gas

Atomic Volume (cc/mol): 32.2

Covalent Radius (pm): 112

Specific Heat (@20°C J/g mol): 0.247

Evaporation Heat (kJ/mol): 9.05

Pauling Negativity Number: 0.0

First Ionizing Energy (kJ/mol): 1350.0

Lattice Structure: Face-Centered Cubic

Lattice Constant (Å): 5.720

CAS Registry Number: 7439-90-9

Krypton Trivia:

  • Sir William Ramsay was awarded the 1904 Nobel Prize in Chemistry for the discovery of the noble gasses, including Krypton.
  • The meter was defined in 1960 as 1,650,763.73 wavelengths of the 605.78 nanometer spectral line from Krypton-86. This standard was replaced in 1983.
  • Krypton is usually inert, but it can form molecules. The first krypton molecule, krypton difluoride (KrF2), was discovered in 1963.
  • Earth's atmosphere has approximately 1 part per million abundance of krypton.
  • Krypton can be obtained by fractional distillation from air.
  • Light bulbs containing krypton gas can produce a bright white light useful for photography and runway lights.
  • Krypton is often used in gas and gas ion lasers.

References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952), CRC Handbook of Chemistry & Physics (18th Ed.) International Atomic Energy Agency ENSDF database (Oct 2010)

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