Radical cations of Me3CSiMe3 and Me3CGeMe3 were detected in hexane solution using the method of time-resolved magnetic field effect. The structures and electronic distributions of neutral molecules Me3CEMe3 and their radical cations: Me3CEMe3 center dot+ (E = C, Si, Ge, Sn) were investigated by DFT PBE/TZ2P calculations. The calculated and the experimental hyperfine coupling constants a(H) are in good agreement. The structures of Me3CSiMe3+center dot, Me3CGeMe3+center dot, and Me3CSnMe3+center dot are in essence a tight radical cation pairs of the type CMe3 center dot/EMe3+center dot. (C) 2008 Published by Elsevier B. V.