Abstract The trimethylsilyl-substituted derivatives of dimethylzinc [(Me 3 Si) n CH 3− n] 2 Zn with n= 1, 2 and 3 give NMR data which are strongly dependent on the substitution grade, which indicates an increasing flattening of the α-carbon atom. Whereas the pyrophoric compounds with n= 0, 1 and 2 are distillable liquids, the air and water resistent bis [tris (trimethylsilyl) methyl] zinc (n= 3) has a melting point of about 300 C. The derivative ...