“…Up to now, cases have been presented where the magnetic impurity is located in a well-defined environment (a substitutional site, an interstitial or a segregated phase), and for which XAS has provided a precise determination of the local environment. It has been possible to describe the site up to several coordination shells in the case of Fe [66] and Mn [80] in GaN, Mn in GaAs [73], As [43] and Ge [82] in Si just to cite a few cases. There exist, however, cases where this situation is more complex and no precise conclusions can be drawn from the analysis of XAS data, in particular due to the fact that the dopant sits in a variety of sites.…”