A delta-MgCl2 was synthesized by reacting metallic magnesium with l-chlorobutane. This salt is extremely anhydrous and shows a high crystallographic disorder and reactivity toward Lewis bases. By using this delta-MgCl2, eight poly(ethylene glycol)/(delta-MgCl2)(x) complexes, with 3.29 x 10(-3) less than or equal to x less than or equal to 7.00 x 10(-1) were synthetized. The interaction between Mg2+ ion and poly(ethylene glycol) (PEG) ligands was investigated by mid and far FT-IR spectroscopy. It was concluded that in these polymer electrolytes : (a) Mg2+ ions could be accommodated in two distinct distributions of coordination sites and (b) PEG chains present a TGT conformation. Conductivity data of PEG 400/(delta-MgCl2)(x) was determined by impedance spectroscopy. The room temperature conductivities of these polymer electrolytes are ca. 1.9 x 10(-5) S cm(-1).