Crystal structure of a magnesium chloride-ethyl formate adduct

The crystal structure of [MgCl2(HCOOC2H5)2]3, obtained by slow crystallization at room temperature from a solution of a-Mgd2 in dry ethyl formate, has been determined by X-ray diffraction. The structure was solved by direct and Fourier methods and refined by least-squares technique. This polymeric adduct is formed by asymmetric units having the formula[MgCl2(HCOOC2H5)2]3 and crystallizes in an orthorhombic cell, space group Pbca (no. 61), a = 20.96(2) Å, b = 37.02(2) Å, C = 9.518(4) Å, V = 7385(8) Å 3, Z = 8 and dc =1.31 g/cm3. The crystalline adduct consists of double-chloro bridged chain polymers in which the magnesium atom is nearly octahedrically coordinated by four chloro atoms and by the carbonyl oxygen atoms of two HCOOC2H5 moieties, which are characterized by a marked crystallographic disorder. The octahedra share two edges by two double-chloro bridges between the magnesium atoms. There are only weak van der Waals interactions among the chains.