Ethylenediammonium tetraaquadisulfatomagnesium(II)

The title compound, [NH3(CH2)2NH3][Mg(SO4)2(H2O)4], was synthesized by the slow evaporation method. Its crystal structure can be described as an alternate stacking of inorganic layers of tetraaquabis(sulfato-O)magnesium [Mg(SO4)2(H2O)4]2− anions ( symmetry) and organic layers of [NH3(CH2)2NH3]2+ cations along the crystallographic b axis. The anions, built up from tetrahedral SO4 units and octahedral Mg(H2O)4O2 units, and the cations are linked together through N—H⋯O hydrogen bonds, forming a three-dimensional network. O—H⋯O interactions are also present.

Grateful thanks are expressed to Dr T. Roisnel (Centre de Diffractomé trie X, Université de Rennes 1) for the X-ray data collection.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: PB2011).
of chemistry too long regarded as opposites can also lead to completely new properties, and opens a wide field of investigations for the chemist. The applications of these "new" materials cover diverse areas as the properties of strength, optics, ferroelectricity and ferroelasticity, electronics and ionic solid ··· Recently, we reported some new organic-inorganic hybrid solids composed of 3d transition metal, sulfate groups and protonated diamine (Rekik et al., 2005;Naïli, et al., 2006;Rekik et al., 2007;Yahyaoui et al., 2007;Rekik et al., 2008;Rekik et al., 2009). In the field of our investigations in the organicinorganic hybrid materials, we report here the chemical preparation and the structural characterization of a new magnesi- The title compound is isostructural with the manganese, iron and cobalt related phases (Chaabouni et al., 1996;Held et al., 2003;Rekik et al., 2008). As it can be seen in figure 1, the asymmetric unit of the title compound contains only one magnesium atom located at a symmetry centre, only one sulfate tetrahedron and ethylenediammonium cation lying about inversion centre. The Mg(II) central atom is octahedrally coordinated by one oxygen atom of sulfate group, two water molecules and the corresponding centrosymmetrically located atoms. Each octahedron around Mg shares two oxygen with two sulfate groups to form trimeric units,  Figure 2 shows that the structure can be described as an alternation between organic and inorganic layers along the crystallographic b axis.

Experimental
Single-crystals of the title compound were grown by slow evaporation at room temperature of an aqueous solution of MgSO 4 .7(H 2 O)/C 2 H 8 N 2 /H 2 SO 4 in a ratio 1:1:1. The product was filtered off and washed with a small amount of distilled water.

Refinement
The aqua H atoms were located in difference map and refined with O-H distance restraints of 0.85 (2) Å and H-H distance restraints of 1.39 (2) Å. H atoms bonded to C and N atomswere positioned geometrically and allowed to ride on their parent atom, with C-H = 0.97 Å, N-H = 0.89 Å and U iso = 1.2U eq (C, N). Fig. 1. A part of the crystal structure of the title compound showing the asymmetric unit (expanded by symmetry to give complete organic cation and trimeric unit) and atom numbering. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen bonds are represented by dashed lines.[Symmetry codes: (I) -x, -y -1, -z; (II) -x -1, -y + 2, -z + 1.]

Special details
Experimental. Data were corrected for Lorentz-polarization effects and an analytical absorption correction (de Meulenaer & Tompa, 1965) was applied. The structure was solved in the P -1 space group by the direct methods (Mg and S) and subsequent difference Fourier syntheses (all other atoms), with an exception for H atoms bonded to C and N atoms which are positioned geometrically.