Actinides continued structure

Crystallographic data (.continued) for transition metal tetrafluorides, 27 98 for transition metal trifluorides, 27 92 Crystallographic disorder, nitrosyl groups, 34 304-305 Crystallography fuscoredoxin, 47 380 prismane protein, 47 232-233 Rieske and Rieske-type proteins, 47 92-109 Crystal radii, of various ions, 2 7 Crystals, 39 402 Crystal structure actinide metals, 31 36 copper-cobalt supetoxide dismutases, 45 ... 

The nature of bonding and its relationship to structure in actinide-containing materials is a subject of continuing interest. From the perspective of nuclear waste isolation, it is important to understand all the factors affecting the longterm stability of actinide ions in potential host materials, be... 

As a result of this disparity, many questions on the structure and bonding of the actinides center on the role of the 5f-electrons. The molecular orbital descriptions for the bonding of the actinide elements continue to evolve. One of the first general models used to describe the chemical bonding in d- and f-electron complexes is the FEUDAL model. FEUDAL is an acronym for f orbitals essentially unaffected d orbitals accommodate ligands . This model is represented in Figure 3, which depicts the molecular orbital... 

Crystalline phosphates and phosphate glasses continue to receive attention as potential hosts for the immobilization and disposal of radionuclides, particularly actinides and waste streams with a high phosphorous content. The principal crystalline phases considered are apatite, silicates with the apatite-structure, and monazite. As has been discussed by Lutze and Ewing (1988a), there are a number of factors that have to be considered in selecting a nuclear waste form. The most important are ... 

Crystalline salts containing both normal and lacunary ions are known, for example, (NH4)5[Zr(PM0i2O49)(PMo O39)] 26H2O [83]. Ever more complex structures containing mixed metals continue to be reported [84,85]. Entrapped lanthanide cations can be present in K28Li55H7[P8W4sOig4] 92H2O [86]. Structural data for various actinide and lanthanide phosphates... 

A rich and diversified organometallic chemistry of the actinide elements has come into existence in the last three decades of the previous century. High reactivities, unusual reaction paths, catalysis, high coordination numbers, and unique structures continue to reward those working in this area. 

When a reactor is shut down radioactive decay of fission products, the actinide isotopes (produced by capture reactions in the fuel) and structural material activation products continues to generate heat (the decay heat) and this. must be accurately predicted so that adequate cooling can be provided. It is also necessary to predict the heating and radioactive emissions associated with the transfer, storage and reprocessing of fuel. 

Figure 26 shows the equations of state, eq. (37), of the actinide metals, calculated by Skriver and co-workers (Skriver et al. 1978, 1980, Brooks et al. 1984), for the fee structure and fig. 27 shows the calculated atomic radii, evaluated from eq. (37). The agreement between theory and experiment implies that the approximations to density functional theory outlined in sect. 3.1 contain the essential physics. Early in the series, Fr-Th, we observe a decrease in radius, which is caused by an increase in the amount of d character (fig. 24). For Th-Pu the calculated atomic radius continues to decrease, but now the cause can be traced to the increasing occupation of the 5f orbitals, which,... 

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