An almost unexplored research field of the ion implantation processes is related to chemical modifications induced in a target by chemically reactive ions. This kind of chemistry is somewhat similar to the “hot atom” chemistry, where chemical transformations are produced by recoil atoms originating from nuclear reactions or radiative decay. XPS technique can provide unique informations on the chemical modifications produced by such processes. XPS results will be reported on silica glasses implanted with titanium, silver and tungsten ions in a dose range from l×1016 to 5×1016 ions cm−2, at energies ranging from 15 keV to few hundreds of keV. Most of samples were also subjected to a second implant with N ions. Radiation damage and chemical effects have been discriminated. Chemical compound formation as well as precipitation of the implanted species have been observed. Interestingly, evidences for reactions between chemical species obtained by the first implant and nitrogen (subsequently implanted) will be reported.