Amorphous nanoclusters of chromium and titanium silicides have been synthesized by implanting 35 keV chromium and 30 keV titanium ions, at a fluence of 1×1017cm−2in amorphous silica. The cluster stoichiometries were [Cr]/[Si]=1.6±0.3 and [Ti]/[Si]=1.1±0.3, respectively, as obtained by energy dispersive spectroscopic x‐ray microanalysis and confirmed by x‐ray photoelectron spectroscopy analysis. Titanium‐implanted ions are more reactive than chromium ones in terms of the formation of chemical bonds with silicon of the host silica matrix. ©1995 American Institute of Physics.