Nomenclature
CAS number: 7439-90-9
Description and references
Kr; at. wt 83.798; at. no. 36. Group VIIIA
(18), also known as Group 0. A noble gas characterized by an electronic
structure in which the outer p subshell is entirely filled.
Naturally occurring stable isotopes (mass numbers): 78 (0.35%);
80 (2.25%); 82 (11.6%); 83 (11.5%); 84 (57.0%); 86 (17.3%); known
artificial radioactive isotopes: 71-77; 79; 81; 85; 87-95; 97. Isoln
from the final residues obtained after evaporation of liq air: Ramsay,
Travers, Proc. Roy. Soc. 63 [A], 405 (1898). Concentration in air: 1.14 ppm by vol.
Obtained commercially from the atmosphere by distillation-liquefaction
process. Prepn: Lepape, Compt. Rend. 187, 231 (1928); Claude, ibid. 581. Monograph:
Argon, Helium and the Rare Gases vols. 1, 2, G. A. Cook, Ed. (Interscience, New York,
1963) 818 pp. Diagnostic use of 81mKr in lung ventilation
imaging: A. Zwijnenburg et al., Clin. Phys. Physiol. Meas. 9, 147 (1988).
Reviews: A. H. Cockett, K. C. Smith, “The Monatomic Gases”
in Comprehensive Inorganic Chemistry vol. 1, J. C. Bailar, Jr. et al., Eds. (Pergamon
Press, Oxford, 1973) pp 139-211; N. Bartlett, F. O. Sladky, “The Chemistry
of Krypton, Xenon and Radon” ibid. pp 213-249; S.-C. Hwang,
W. R. Weltmer, Jr. in Kirk-Othmer Encyclopedia
of Chemical Technology vol. 13 (John Wiley
& Sons, 4th ed., 1995) pp 1-38; G. J. Schrobilgen, J. M. Whalen, ibid. pp 38-53; Chemistry of the Elements, N. N. Greenwood, A. Earnshaw, Eds. (Pergamon Press, New York, 1984)
pp 1042-1059.
Properties
Colorless, odorless, inert, monatomic gas; non-flammable.
Will form compds with highly electronegative elements such as O,
F, Cl. Condenses to a colorless liquid. Triple pt temp 115.95 K,
press 73.15 kPa. Critical temp 209.4 K, critical press 5502 kPa,
critical d 908 kg/m3. Gas: d0 (101.3 kPa) 3.7493 kg/m3, d
(normal bp) 8.6 kg/m3. Liquid:
normal bp 153.35°, d (normal bp) 2415 kg/m3, d (triple pt) 2451 kg/m3, heat of vaporization (normal bp) 9.050 kJ/mol.
Solid: d (triple pt) 2826 kg/m3, heat of vaporization (triple pt) 10.77 kJ/mol,
heat of fusion (triple pt) 1.64 kJ/mol; solid form exists as face-centered
cubic crystals at normal pressure. Excitation potentials: 9.91;
10.03; 10.56; 10.64 ev; ionization potentials: 14.00; 14.66 ev:
Brocklehurst, Q. Rev. Chem. Soc. 22, 147 (1968). Soly of gas in water (20°): 59.4 cm3/kg water. Slightly soluble in water with formation of a
hydrate; ideal formula Kr.5.75H2O. A hexadeuterate has
been prepd. Soluble in liquid oxygen. Emission spectra: T. Jacksier,
R. M. Barnes, Appl. Spectrosc. 48, 65 (1994).Derivative
Krypton difluoride.
Nomenclature
CAS number: 13773-81-4
F
2Kr; mol wt 121.79.
F 31.20%, Kr 68.81%.
Description and references
Prepn: Turner, Pimentel, Science 140, 974 (1963).
Properties
Colorless solid; decomposes rapidly at room temperature.
d (calc) 3.24. Vapor
pressure (mm Hg): 10 ±1 at 15.5°; 29 ±2 at 0°; 73 ±3 at 15°.Caution
Can act as a simple asphyxiant by
displacing air. See: Matheson
Gas Data Book (Matheson Co., Inc., 4th ed., East Rutherford,
NJ, 1966) pp 313-314.Use
As gas filler in special purpose electric bulbs.
To initiate and sustain the arc in metal-vapor discharge tubes, such
as mercury and sodium vapor lamps. To determine surface areas of
fine solids by adsorption techniques.
Therapeutic Category
81mKr as diagnostic aid (radioactive imaging agent).
Keywords
Krypton 81mKr: Diagnostic Aid (Radioactive Imaging Agent)