Bromine nuclear properties

In comprehensive treatments of the chemistry of the halogens the properties of fluorine compounds are sufficiently different to motivate a separate chapter. A similar distinction is also practical in a discussion of manifestations of nuclear properties of the halogens, since all stable isotopes of chlorine, bromine and iodine have... 

Concerning the nuclear properties it may be noted that the ratio of the nuclear quadrupole moments of the isotopes of chlorine and bromine have been determined with considerably higher accuracy than have the individual quadrupole moments. NMR spectroscopy has been frequently applied to determine nuclear magnetic moments and all the nuclear magnetic properties listed in Table 1.1 were obtained from... 

When simple Hquids like naphtha are cracked, it may be possible to determine the feed components by gas chromatography combined with mass spectrometry (gc/ms) (30). However, when gas oil is cracked, complete analysis of the feed may not be possible. Therefore, some simple definitions are used to characterize the feed. When available, paraffins, olefins, naphthenes, and aromatics (PONA) content serves as a key property. When PONA is not available, the Bureau of Mines Correlation Index (BMCI) is used. Other properties like specific gravity, ASTM distillation, viscosity, refractive index. Conradson Carbon, and Bromine Number are also used to characterize the feed. In recent years even nuclear magnetic resonance spectroscopy has been... 

Fullerenes can be derivatized by various means. For example, reaction with fluorine gas proceeds stepwise to the formation of colorless CeoFeo, which, according to the 19F nuclear magnetic resonance (NMR) spectrum, contains just one type of F site and so evidently retains a high degree of symmetry.9 In view of the low adhesion typical of fluorocarbons, this spherical molecule is expected to have extraordinary lubricant properties. Curiously, bromination of Ceo is reversible on heating otherwise, the reactions of fullerenes resemble those of alkenes or arenes (aromatic hydrocarbons). 

The NMR properties of the halogens are given in Table 1. The isotopes of chlorine, bromine and iodine have a spin I > Vi and so possess a quadrupole moment. The technique of nuclear quadrupole resonance (NQR) will not be examined in this chapter. The T9F NMR spectra will be discussed as well as the effects of halogen on proton spectra. 

From these two main groups of the Periodic System of Elements, only the elements bromine, iodine, rubidium and cesium are produced by nuclear fission to an extent worth mentioning. Iodine and cesium are of particular interest during plant normal operation as well as in accident situations, because of their comparatively high fission yields, their enhanced mobility in the fuel at higher temperatures and the radiotoxicity of some of their isotopes. Both elements are often summarized under the term volatile fission products their similar properties justify their treatment in the same context, despite pronounced differences in their basic chemical behavior. 

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