Abstract It has been theoretically predicted that manganese atoms in silicon matrix tend to form dimers which can show both ferro‐ and antiferromagnetic properties. One might expect that the significant part of such dimers (N‐mers) should be spattered as cluster ions while SIMS measurement. We have investigated samples of silicon wafers implanted with manganese ions and annealed. In the solid solution the probability of the situation when N doped atoms are nearest neighbours is proportional to Nth power of concentration. However, if in the solution the process of enhancement of neighbouring impurity atoms number takes place, the cluster ion signal should exceed the power law. We have verified the validity of this statement in ion implanted solutions of B and Mn in silicon. SIMS measurements in annealed samples show that the profile of Mn 2 and Mn 3 ions essentially exceed respectively the square and the cube of manganese concentration. Quantitative estimation shows that in the annealed sample at some depths manganese dimers contain about 10% of total Mn atoms. The connection between the obtained profiles and magnetic measurements is discussed. Copyright © 2008 John Wiley & Sons, Ltd.