Diamagnetic uranium compounds

Table V. Calculated 235U Absolute Shieldings in Diamagnetic Uranium Compounds. ...

We have used the Pauli formalism in its scalar and spin-orbit versions as well as the allelectron ZORA approach to calculate NMR shieldings and chemical shifts in various diamagnetic (formally J°) uranium compounds. Preliminary results will be presented in the following. 

Uranium(vi) compounds are expected to be diamagnetic, with their Sq (f°) ground state. However, compounds like UFe and uranyl complexes in fact exhibit temperature-independent paramagnetism, explained by a coupling of paramagnetic excited states with the ground state. 

The monochlorotris-silylamides, [(Me3Si)3N]3MCI, of the two most readily accessible actinide elements, thorium and uranium, have been prepared by reaction of three molar equivalents of sodium bis(trimethylsilyl)amide and the metal chloride in tetrahydrofuran. The thorium derivative is a colorless, diamagnetic, pentane soluble compound which is rtionomeric in the gas phase (by mass spectrometry) (19, 20). The tan uranium analogue is paramagnetic (yB = 2.8 B.M.) (20). 

Bismuth is the most diamagnetic of all metals and has low thermal conductivity. Since bismuth expands upon solidification, it is used to make castings for objects subjected to high temperatures. It is used as a replacement for lead in solders, shot for hunting, fishing sinkers, ceramic glazes, and brasses for plumbing applications. It is also used as a carrier for (an isotope of uranium) fuel in atomic reactors. Ionic compounds of bismuth are used in cosmetics and medicine. 

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