Microstructure control of magnesium dichloride crystallites by electron donors: The effect of methanol

Abstract The ability to control the microstructure of magnesium dichloride (MgCl 2 ) crystallites by electron donors was demonstrated by quantum chemical calculations, using methanol as a model donor. Investigation of sets of differently shaped MgCl 2 crystallites showed the dominance of the five-fold coordinated (1 0 0) crystal surface over the four-fold coordinated (1 1 0) surface to emerge as a factor increasing crystallite stability. To study the role of electron donors in controlling MgCl 2 crystallite shape, crystallites were saturated with methanol. The stability order of the crystallites was significantly affected by donor adsorption. Reverse to the case of pure MgCl 2 , crystallites with the highest (1 1 0) to (1 0 0) surface site ratio became the most stable after donor adsorption. This indicates control of the shape of MgCl 2 crystallites to be attainable by appropriate choice of electron donor, a result utilizable in heterogeneous Ziegler–Natta olefin polymerization catalysis.