Mendelevium oxidation states

This oxidation state was indicated in the cocrystallization of Md with CsCl and RbCl after the coreduction of Md + and Sm + with Mg in an ethanol-7 M HC1 solution. Mendelevium was also found enriched in Rb2PtCl precipitates, a specific carrier for the larger ions of the alkali metals. These results were explained by a stabilization of the monovalent ion due to completing the f shell which would give the 5f- electronic configuration. 

Mendelevium — (Dmitri Mendeleev [1834-1907]), Md at. wt. (258) at. no. 101 m.p. 827°C valence +2, +3. Mendelevium, the ninth transuranium element of the actinide series to be discovered, was first identified by Ghiorso, Harvey, Choppin, Thompson, and Seaborg early in 1955 as a result of the bombardment of the isotope Es with helium ions in the Berkeley 60-inch cyclotron. The isotope produced was Md, which has a half-life of 78 min. This first identification was notable in that Md was synthesized on a one-atom-at-a-time basis. Nineteen isotopes and isomers are now recognized. Md has a half-life of 51.5 days. This isotope has been produced by the bombardment of an isotope of einsteinium with ions of helium. It now appears possible that eventually enough Md can be made so that some of its physical properties can be determined. Md has been used to elucidate some of the chemical properties of mendelevium in aqueous solution. Experiments seem to show that the element possesses a moderately stable dipositive (II) oxidation state in addition to the tripositive (III) oxidation state, which is characteristic of actinide elements. 

The -I- 3 oxidation state is the most stable oxidation state for americium through mendelevium and for lawrencium. It is easy to produce Pu and Np ", but is such a strong reducing agent that it is difficult to keep in solution. 

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