G3-Global and -Local Minima of XC2H4 + Structural Isomers where X = Li to Br

B3lyp/6-311+g** and g3 levels of theory reveal that cyclic and 1-substituted isomers are either global or local minima for xc2h4 + structural isomers when x is ch3 or an element of groups v, vi and vii. π-bridged structures are global minima when x is an element of groups i, ii and iii, sih3 and geh3. the large electrophilicity of c+ in substituted ethyl cations and the position of x in the periodic table are the main factors that determine the structure of the global minima