Chlorine-Bromine Combination Isotope

Chlorine-Bromine Combination Isotope Intensities Reference Compounds under Electron-Impact Conditions in Mass Spectrometry... 

Rule 4 The actual number of chlorine or bromine atoms can be derived from the table in the section entitled Chlorine-Bromine Combination Isotope Intensities. ... 

Chlorine-Bromine Combination Isotope Intensities Section 16 Health and Safety Information... 

CHLORINE-BROMINE COMBINATION ISOTOPE INTENSITIES Thomas J. Bruno and Paris D. N. Svoronos... 

Isotopic Abundances of Various Combinations of Chlorine, Bromine, Sulfur, and Silicon... 

The two naturally occurring isotopes of chlorine are (34.9689 u, 75.77%) and (36.9658 u, 24.23%). The two naturally occurring isotopes of bromine are Br (78.9183 u, 50.69%) and Br (80.9163 u, 49.31%). Chlorine and bromine combine to form bromine monochloride, BrCl. Sketch a mass spectrum for BrCl with the relative number of molecules plotted against molecular mass (similar to Figure 2-14). 

Table 9.12 Intensities of isotope peaks (relative to the parent peak) for combinations of bromine and chlorine...

Fig. 3.3. Calculated isotopic patterns for combinations of bromine and chlorine. The peak shown at zero position corresponds to the monoisotopic ion at m/z X. The isotopic peaks are then located at m/z = X+2, 4, 6,. .. The numerical value of X is given by the mass number of the monoisotopic combination, e.g., 70 u for CI2.

Table 2.3 Intensities of Isotope Peaks (Relative to the Molecular Ion) for Combinations of Bromine and Chlorine...

Fig. 3.77 Isotope abundances for combinations of chlorine and bromine atoms.

Due to the distinctive mass spectral patterns caused by the presence of chlorine and bromine in a molecule, interpretation of a mass spectrum can be much easier if the results of the relative isotopic concentrations are known. The following table provides peak intensities (relative to the molecular ion (M+) at an intensity normalized to 100%) for various combinations of chlorine and bromine atoms, assuming the absence of all other elements except carbon and hydrogen.1 The mass abundance calculations were based on the most recent atomic mass data.1... 

The relative abundances of the peaks (molecular ion, M + 2, M + 4, and so on) have been calculated by Beynon et al. (1968) for compounds containing chlorine and bromine (atoms other than chlorine and bromine were ignored). A portion of these results is presented here, somewhat modified, as Table 1.5. We can now tell what combination of chlorine and bromine atoms is present. It should be noted that Table 1.4 presents the isotope contributions in terms of percent of the molecular ion peak. Figure 1.29 provides the corresponding bar graphs. 

RELATIVE INTENSITIES OF ISOTOPE PEAKS FOR VARIOUS COMBINATIONS OF BROMINE AND CHLORINE... 

Table 8.6 in Section 8.5 can be used to determine what the ratio of the intensities of the molecular ion and isotopic peaks should be when more than one chlorine or bromine is present in the same molecule. The mass spectra of dichloromethane (Fig. 8.51), dibromomethane (Fig. 8.52), and l-bromo-2-chloroethane (Fig. 8.53) are included here to illustrate some of the combinations of halogens listed in Table 8.6. 

TABLE 6.4. Abundances of Isotopic Peaks (percent) for Combinations of Chlorine and Bromine... 

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