EXAFS and LAXS of Grignard Compounds

Despite numerous investigations of Grignard compounds, almost no information exists about intra- and interatomic distances of these reagents in solution. This is not necessarily remarkable, since the methods of physical chemistry discussed in the previous section are of course not able to provide such information. But X-ray absorption spectroscopy (EXAFS) and largo angle X-rav scattering (LAXS) can. 

In 1987 1. Persson et al, published the results of their F.XAFS and LAXS investigations of magnesium bromide and iodide in diethyl ether and Till- 1104], It was the purpose to get information about the possible structures of these two compounds in solution. MgX. species 

Data analysis was perlornied with the computer program XPPAKG. which was developed by R.A. Scott and co-workers il Stanford University. 

The Fourier transforms of all Grignard compounds show one major peak that corresponds to the expected Br—Mg distance. Fourier tillering was used to isolate this peak. The subsequent curve-fitting leads to the results given in Table 10.4. A wider tiller was also applied to see if there was any contribution from other buckscatierers and if such a second shell could 

In principle, these considerations are right and certainly play a role in the present case. In our opinion, however, they cannot adequately explain 

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