catena-Poly[[diaquabis(2-ethyl-1H-imidazole-κN 3)cadmium]-μ-sulfato-κ2 O:O′]

In the title one-dimensional coordination polymer, [Cd(SO4)(C5H8N2)2(H2O)2]n, the CdII atom (site symmetry 2) is coordinated by two sulfate O atoms, two water molecules and two 2-ethylimidazole ligands in a distorted cis-CdN2O4 octahedral geometry. The water molecules have a cis disposition. The bridging sulfate ions (site symmetry 2) link the CdII ions into a polymeric chain extending along [001]. The chains are linked by N—H⋯O and O—H⋯O hydrogen bonds. The terminal –CH3 group of the ligand is disordered over two orientations in a 0.61 (5):0.39 (5) ratio.

In the title one-dimensional coordination polymer, [Cd(SO 4 )-(C 5 H 8 N 2 ) 2 (H 2 O) 2 ] n , the Cd II atom (site symmetry 2) is coordinated by two sulfate O atoms, two water molecules and two 2-ethylimidazole ligands in a distorted cis-CdN 2 O 4 octahedral geometry. The water molecules have a cis disposition. The bridging sulfate ions (site symmetry 2) link the Cd II ions into a polymeric chain extending along [001]. The chains are linked by N-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds. The terminal -CH 3 group of the ligand is disordered over two orientations in a 0.61 (5):0.39 (5) ratio.

Related literature
For background to ferroelectric materials, see: Zhang et al. (2010). For a related structure, see: Zhu & Yu (2011).
The author thanks an anonymous advisor from the Ordered Matter Science Research Centre, Southeast University, for great help in the revision of this paper.

Chua-Hua Yu Comment
According to finding potential ferroelectric phase change materials via dielectric constant measurements of compounds on the basis of temperature (Zhang et al., 2010). Unluckily, no dielectric anomaly was observed ranging from 120 K to near 290 K. In this report the crystal structure of the title compound is herein reported. A structure chart showing the structure of the title compound (Scheme 1). A viewgraph of with the symmetry related fragments and atom-numbering scheme is shown in Fig (Table 1).

Experimental
2.4 g (25 mmol) of 2-ethylimidazole was dissolved in 20 ml water, dropping 1.23 g (12.5 mmol) of H 2 SO 4 into it, and 6.4 g (8.3 mmol) 3CdSO 4 .8H 2 O was added to the solution. After stirring the mixture for several minutes, 6.18 g (25 mmol) of Ba(NO 2 ) 2 was joined into it forming precipitation. The turbid liquid was filtered to give a light yellow solution. Yellow blocks were obtained, but not the expecting things, by the slow evaporation of the above solution after sever days at the ambient temperature.

Refinement
All H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms but for H1A and H1B with C-H = 0.93 Å, with U iso (H) = 1.2 U iso (C).

catena-Poly[[diaquabis(2-ethyl-1H-imidazole-κN 3 )cadmium]-µ-sulfato-κ 2 O:O′]
Crystal data Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ. (