Uranium neutron diffraction studies

Structural work on UO2F2 (24,246,247) has gradually been refined over the years, and a neutron diffraction study has shown that UO2F2 has a trigonal structure in which the uranium is eight-coordinate... 

At present we do not know why UCr4Alg does not follow the Curie-Weiss law (Baran et al. 1987). Magnetic order as the cause of this behavior is excluded by a neutron diffraction study (Bouree-Vigneron et al. 1990). Therefore, the cause could be a partial delocalization of the uranium 5f electrons. 

The hydride decomposes at somewhat higher temperatures to give extremely reactive, finely divided metal. A study of the isostructural deuteride by X-ray and neutron diffraction shows that the deuterium atoms lie in a distorted tetrahedron equidistant from four uranium atoms no U—U bonds appear to be present, and the U—D distance is 2.32 A. The stoichiometric hydride UH3 can be obtained, but the stability of the product with a slight deficiency of hydrogen is greater. 

Recent very detailed neutron powder-diffraction studies performed by Lawson et al. (1986) revealed very complex magnetic structures below 30 K which are schematically drawn in fig. 3.5. The ferromagnetic structure below 30 K consists of alternating layers of magnetic (with a moment of l)iB) denoted by 1 and non-magnetic uranium atoms denoted by 0 on which there is superimposed a non-colhnear antiferromagnetic structure which itself re-orders at 20 K (near the temperature of the second transition indicated by the bulk measurements). The ferromagnetic... 

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