Neptunium compounds

That magnetic measurements often raise more problems than they solve, is demonstrated for the indicated compound. We prepared a series of [ (C2H5N] i,An(NSC) e compounds (An = Th, U, Np, Pu) with cubic coordination of the actinide ion. We derived a consistent interpretation of the magnetic and optical properties of the uranium and the neptunium compounds (6 ). In the case of Pu we expect an isolated T1 ground state and a first excited state at about 728 cm-1. To our surprise we found a magnetic ground state much more pronounced than in the case of the hexachloro-complex, Fig. 4. 

The problem could be stated from another point of view. In an isostructural series the uranium and neptunium compounds tend to be itinerant electron magnets or band magnets (like iron) and their orbital contribution is at least partially quenched. For much heavier actinides we know that the compounds will make local moment magnets with orbital contributions. It is quite possible that in between these two clear cut forms of magnetism that the intermediate case could be dominated by fluctuations, and no recognizable form of magnetism would occur. To state that the... 

All isotopes of neptunium are highly radioactive and are hazardous and thus need to be carefully used in controlled laboratory settings. These isotopes as well as neptuniums compounds are radioactive poisons. 

LaChapette, T. J., L. B. Magnusson, and J. C. Hindman The Chemistry of Neptunium. First Preparation and Solubilities of some Neptunium Compounds in Aqueous Solution. In G. T. Seaborg, J. J. Katz, and W. M. Manning (Eds.), The Transuranium Elements, National Nuclear Energy Series, Div. IV, Vol. 14B, p. 1097. New York McGraw-Hill 1949. 

The Mossbauer spectrum of the neptunium compound [(C8Hg)2Np] confirms that the metal is in the trivalent oxidation state, and suggests a lower overall degree of covalency in metal-ligand bonding than in tetravalent derivatives. Most recently, the reduction route has been extended... 

Neptunium dioxide, Np03, is the most stable of the neptunium oxides. It crystallizes with the fluorite structure of all the actinide dioxides, with a crystalline density of 11.14 g/cm . It can be formed from the thermal decomposition of other neptunium compounds, such as the hydroxide, the nitrate, or the oxalate, in the temperature range of 600 to 1000°C. High-fired NpOj can be dissolved in hot concentrated nitric acid containing small amounts of fluoride. 

Fig. 18.5 The known ranges for the chemical isomer shift in neptunium compounds correlated with the formal oxidation state.

Plutonium and neptunium nitrides were studied for the application to advanced fast breeder reactor (FBR) fuels. Details on the application of nuclear fuels is available in the reference (Matzke 1986). Fundamental properties of these plutonium and neptunium compounds are reviewed in the Chemical Thermodynamics of Neptunium and Plutonium (Lemire et al. 2001) issued by OECD/NEA (Organization for Economic Co-operation and... 

The other known actinide tetrakis(cyclopentadienyls) are PaCp4 [51] and NpCp4 [52]. The protactinium compound was synthesized by the route of equation (22.28) while the neptunium compound is accessible via the more convenient procedure of equation (22.29) ... 

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