SYNTHESIS, CRYSTAL-STRUCTURE AND THERMAL-STABILITY OF THE MGCL2 FORMAMIDE ADDUCT

The reaction of alpha-MgCl2 with formamide affords the MgCl2(HCONH2)6 adduct which was obtained as crystals suitable for X-ray analysis. M(r ) = 730.91, monoclinic, space group P2(1)/a with a = 9.199(4), b = 7.4 13(2), c = 12.227(6) angstrom, alpha = 90.00, beta = 91.5(l), gamma = 90.00-degrees, V = 833.5(6) angstrom3, D(x) = 1.46 g cm-3, lambda(Mo K alpha) = 0.71069 angstrom, mu = 4.17 cm-1, F(000) = 380, T = 298 K; ob served reflections 1198, R = 0.048, R(w) = 0.047. Such adduct shows a three-dimensional polymeric structure formed through hydrogen bonds be tween the -NH2 groups and the chloride ions. Each magnesium atom appea rs to be octahedrally coordinated by six formamide molecules through t he carbonyl oxygen atom. The thermal stability of the adduct has also been investigated by thermogravimetric analysis and the obtained TG cu rve shows that the thermal elimination of the coordinated Lewis base a ppears to be the result of more than one step.