Neptunium - Chemistry

Chemistry

This element has four ionic oxidation states while in solution:

  • Np3+ (pale purple), analogous to the rare earth ion Pm3+
  • Np4+ (yellow-green)
  • NpO+
    2 (green-blue)
  • NpO2+
    2 (pale pink)

Neptunium(III) hydroxide is not soluble in water and does not dissolve in excess alkali. Neptunium(III) is susceptible to oxidation in contact to air forming neptunium(IV).

Neptunium forms tri- and tetrahalides such as NpF3, NpF4, NpCl4, NpBr3, NpI3, and oxides of the various compositions such as are found in the uranium-oxygen system, including Np3O8 and NpO2.

Neptunium hexafluoride, NpF6, is volatile like uranium hexafluoride.

Further information: fluoride volatility and uranium enrichment

Neptunium, like protactinium, uranium, plutonium, and americium readily forms a linear dioxo neptunyl core (NpO2n+), in its 5+ and 6+ oxidation states, which readily complexes with hard O-donor ligands such as OH–, NO2–, NO3–, and SO42– to form soluble anionic complexes which tend to be readily mobile with low affinities to soil.

  • NpO2(OH)2–
  • NpO2(CO3)–
  • NpO2(CO3)23–
  • NpO2(CO3)35–
See also: Actinides in the environment

Read more about this topic:  Neptunium

Famous quotes containing the word chemistry:

    “...some sort of false logic has crept into our schools, for the people whom I have seen doing housework or cooking know nothing of botany or chemistry, and the people who know botany and chemistry do not cook or sweep. The conclusion seems to be, if one knows chemistry she must not cook or do housework.”
    —Ellen Henrietta Swallow Richards (1842–1911)

    “Science with its retorts would have put me to sleep; it was the opportunity to be ignorant that I improved. It suggested to me that there was something to be seen if one had eyes. It made a believer of me more than before. I believed that the woods were not tenantless, but choke-full of honest spirits as good as myself any day,—not an empty chamber, in which chemistry was left to work alone, but an inhabited house,—and for a few moments I enjoyed fellowship with them.”
    —Henry David Thoreau (1817–1862)

    “For me chemistry represented an indefinite cloud of future potentialities which enveloped my life to come in black volutes torn by fiery flashes, like those which had hidden Mount Sinai. Like Moses, from that cloud I expected my law, the principle of order in me, around me, and in the world.... I would watch the buds swell in spring, the mica glint in the granite, my own hands, and I would say to myself: “I will understand this, too, I will understand everything.””
    —Primo Levi (1919–1987)