Nomenclature
CAS number: 7440-07-5
Description and references
Pu; at. no. 94; valences 3, 4, 5, 6, 7. No
stable nuclides, known isotopes (mass numbers): 232-246. Longest-lived
known isotopes: 242Pu (T 1/2 3.76 × 105 years, α-emitter, rel. at. mass 242.0587), 244 (T 1/2 8.26 ×
107 years, α-emitter, rel. at. mass 244.0642). Commercially
useful isotopes: 238Pu (T 1/2 87.74 years; α-emitter,
rel. at. mass 238.0496); 239Pu (T 1/2 2.41 × 104 years; α-emitter, rel. at. mass 239.0522). Occurrence in
the earth's crust: 10-22%. Discovery of isotope 238Pu: G. T. Seaborg et al., Phys. Rev. 69, 366, 367 (1946); of isotope 239Pu: J. W. Kennedy et al., ibid. 70, 555 (1946). Isoln of 239Pu from pitchblende: G. T. Seaborg, M. L. Perlman, J. Am. Chem. Soc. 70, 1571 (1948).
Prepn of metal: B. B. Cunningham, L. B. Werner, ibid. 71, 1521 (1949). Chemical properties:
Seaborg, Wahl, ibid. 1128; Harvey et al., J. Chem. Soc. 1947, 1010. Reviews: J. M. Cleveland, The Chemistry
of Plutonium (Gordon & Breach, New York, 1970) 653
pp; C. Keller, The Chemistry of the Transuranium
Elements (Verlag Chemie, Weinheim, English Ed., 1971)
pp 333-484; Comprehensive Inorganic Chemistry vol. 5, J. C. Bailar, Jr. et al., Eds. (Pergamon
Press, Oxford, 1973) passim; Handb.
Exp. Pharmakol. 36, 307-688 (1973); F. Weigel
in Kirk-Othmer Encyclopedia of Chemical Technology vol. 18 (Wiley-Interscience, New York, 3rd ed., 1982)
pp 278-301; Plutonium Chemistry, W. T. Carnall, G. R. Choppin, Eds. (Am. Chem. Soc., Washington,
D.C., 1983) 484 pp; F. Weigel et al. in The Chemistry of the Actinide Elements vol. 1, J. J. Katz et al., Eds. (Chapman and Hall,
New York, 1986) pp 499-886. Review of toxicology: W. J. Bair, R.
C. Thompson, Science 183, 715-722 (1974); and health effects: Toxicological
Profile for Plutonium (PB91-180406, 1990) 206 pp.
Properties
Silvery-white metal. Highly reactive. Oxidizes
readily in dry air and oxygen, rate increases in presence of moisture.
Six allotropic forms: simple monoclinic α-form, d21 19.86, transforms to β-form
at 122 ±4°; body-centered monoclinic β-form, d190 17.70, transforms to γ-form
at 207 ±5°; face-centered orthorhombic γ-form, d235 17.14, transforms to δ-form
at 315 ±3°; face-centered cubic δ-form, d320 15.92, transforms to δ′-form at 457 ±2°;
body-centered tetragonal δ′-form, d405 16.00, transforms to ε-form at 479 ±4°; body-centered
cubic ε-form, d490 16.51, transforms to liquid at mp 640 ±2°.Derivative
Trivalent plutonium.
Properties
Weak reducing agent. Stable in soln in absence
of air. Slowly oxidized to the tetravalent plutonium by atmospheric
oxygen, by permanganate in acid soln in the cold; oxidized to the
hexavalent form by permanganate at 60°. Trivalent salts are blue;
form complexes very readily; form a series of double sulfates. Crystal
structure of the complex and double salts: Zachariasen, J. Am. Chem. Soc. 70, 2147 (1948).Derivative
Tetravalent plutonium.
Properties
Reduced in aq soln to the trivalent form by sulfur
dioxide, hydroxylamine hydrochloride, hydrazine hydrochloride, the
uranous ion, the iodide ion; by shaking with mercury in chloride soln;
electrolytically at a platinum cathode. Tetravalent salts are pink
or greenish; form complexes very readily.Derivative
Hexavalent plutonium.
Properties
Obtained by the action of strong oxidizing agents
(ceric salts, dichromates, permanganates, or hot bromate soln contg
nitric acid) on the tri- or tetravalent form. Reduced to tri- or
tetravalent plutonium by sulfur dioxide or ferrocyanide.Caution
Radiation hazard; handling requires
special equipment and shielding facilities. Animal studies have indicated
that inhaled 239Pu as particulate matter may remain in
the lungs, or move to the bones, liver or other body organs, and over
a period of time may give rise to neoplasms due to its α-emitting
radioactive decay. See Katz et al., loc. cit. vol. 2, p. 1128, 1182-1188. Max permissible concn of 238Pu in air: 7 × 10-13 μCurie/cc; of 239Pu in air: 6 × 10-13 μCurie/cc: Natl. Bur. Stand. Handb. 69, 87 (1959). See also Handb. Exp. Pharmakol. loc. cit.Use
238Pu as heat source; as radioisotope
thermoelectric generator; in radionuclide batteries for pacemakers.
239Pu as fuel in atomic weapons and nuclear power reactors.