Magnetism of the heavy 5f elements

Huray, Paul G.; Nave, S.E.; Haire, R.G.

doi:10.1016/0022-5088(83)90175-3

Cited by 33 publications

(11 citation statements)

References 3 publications

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“…The magnetic susceptibility and enthalpy of formation of ^'^'CmjOs were recently measured [43]; the susceptibility was normal (except for an antiferromagnetic transition at 12 K that could not be observed with Cm because of its very high self-heating). The enthalpy of formation is consistent with data on corresponding lanthanides but not with PujOj, the only other actinide sesquoxide for which AHf is known [43,44], Magnetic susceptibilities of Cm02, CmF4, and BaCmOa, even with ^'^'Cm, show unexpected temperature-dependent paramagnetism, apparently due to varying amounts of Cm(III) in these Compounds [45][46][47]. Further studies of the solid State chemistry of curium and neighboring elements are important because this is the group of 5/elements with electronic structures intermediate between localized (bonding) and itinerant (magnetic) behavior [30].…”

Section: Curiumsupporting

confidence: 83%

Advances in Chemistry of the Actinide Elements

Morss

1984

Radiochimica Acta

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Recent research accomplishments that elucidate the bonding and reactivity of the actinides are highlighted in this review. Improved syntheses of protactinium and transplutonium metals and Compounds have led to determination of physical properties that reveal effects of 5f interactions. Theimodynamic measurements on metals, aqueous ions, and oxides have yielded more systematic understanding of the chemistry of the entire actinide series. Advances in bonding include the preparation of new organoactinide Compounds with strong a and TT metal-carbon and metal-hydrogen bonds; the development of new actinide complexing, sequestering, and extracting agents; and the study of chemical consequences of radioactive decay on oxides and halides. New techniques that impact actinide chemistry are laser fluorescence and photochemistry, radiocoulometry, and pulse radiolysis. Progress has also been made in outlining the basic chemical behavior of the heaviest actinides and the transactinides.Two isomorphs of ThBr4 are known, the well-known /3-ThBr4 and a low-temperature, poorly-characterized a-ThBr4. Below 92 K, j3-ThBr4 displays Splitting of a Raman Vibration and of a bromine nuclear quadrupole resonance line, and new X-ray and neutron diffraction lines appear [2,7]. These observations are not consistent with any conventional superlattice of the tetragonal unit cell, and are caused by a second-order phase transition in which bromine atoms along the c ciystallographic axis are displaced sinusoidally from their sites with a repeating distance of 3.201 c. This phenomenon is a subject of intense investigation and illustrates how careful measurements on pure, Single ciystals can reveal new scientific ideas.

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Section: Curiumsupporting

confidence: 83%

Advances in Chemistry of the Actinide Elements

Morss

1984

Radiochimica Acta

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“…1 a schematic representation of the magnetic properties of the actinide metals is shown [1]. One can see that the magnetic ordering is observed only for heavier actinides beginning from curium.…”

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confidence: 99%

Magnetism of Uranium Intermetallics

Suski

1997

Acta Phys. Pol. A

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In the present review first the magnetic properties of the actinide metals are presented with a special emphasis on the uranium. Then the reason for starting the research on the uranium compounds in Wrocław is given together with a brief description of the magnetic properties of the binary compounds. The comparison with the rare-earth ternaries illustrates the difficulties in interpretation of the physical measurements of the uranium intermetallics in which the uranium as well as the transition metal atoms contribute to the magnetic ordering. Further, we present the features which could indicate the true contribution of both partners. However, we also stress that some of the properties which seem to prove the magnetic order on the uranium atom could result from particular crystal or band structure.PACS numbers: 75.30. Cr, 75.30.Gw, 75.50.Cc, Actinide metals form the last known family in the periodic table of the elements. Majority of them have been obtained artificially in the nuclear reactions. Although their identity results from the development of the 5f shell, the similarity to other f electron family (lanthanides) is limited to the heavier representatives of the 5f group. The lighter actinides are very much like anomalous lanthanides, e.g. Ce, and particularly uranium and its compounds under some circumstances exhibit some similarity to the transition elements.In Fig. 1 a schematic representation of the magnetic properties of the actinide metals is shown [1]. One can see that the magnetic ordering is observed only for heavier actinides beginning from curium. Some indication of localized magnetic moment can be detected for americium and these behaviors suggest a similarity of these elements to lanthanides. Now, the peculiarities of physical properties of the uranium metal will be briefly discussed, because this element is a component of the compounds which are the subject of the present review. At low temperature, numerous physical properties of uranium exhibit puzzling features. At 43 K there is sudden expansion of the crystallographic orthorhombic cell, and the elastic constants show anomalous behavior. The similar anomalies are also observed at 23 and 37 K [2], which are (77)

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“…The last two phases are low symmetry structures with relatively low volume and might be indicative of the participation of the 5f electrons in bonding. 7,8 Experiments showed that the magnetic susceptibility of Am metal is almost temperature independent, with a 5f 6 configuration and zero values of spin (S), orbital (L), and total (J) magnetic moments [9][10][11] . Valence band ultraviolet photoemission data supports the localized character of the Am 5f electrons in an f 6 configuration [12][13][14] .…”

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confidence: 99%