[en] Structure and composition of precipitates of nickel atoms in monocrystalline silicon were investigated by electron-probe microanalysis. precipitates were found to consist of silicides of nickel involving some technological impurities and have needle, disk and ball forms, which can disintegrate under influence of external pressures. Because of distinct environmental conditions around precipitates of various forms their disintegration also differs from each other and it leads to corresponding alteration of crystals electrophysical parameter. (author)