Abstract Equilibrium constants are reported for scrambling of the fluoro and azido groups with chloro, cyanato, methoxyl, methylthio, and dimethylamino groups on the dimethylsilicon moiety. The ΔF values obtained from these constants show that fluorine lies first in the halogen series (eg F, Cl, Br) with respect to exchange with various other substituents and that the azido groups acts as a pseudohalide. The mixed species (CH 3) 2 SiF (N 3),(CH 3 ...