Synthesis, structural and electrical properties of [C 2 H 10 N 2 ][(SnCl(NCS) 2 ] 2 Sahel Karoui a , Slaheddine Kamoun a,n , Amor Jouini b a Laboratoire ge´nie de mate ´riaux et environnement, ENIS, BP.1173,3038- Sfax, Universite´ de Sfax, Tunisia b Laboratoire de Chimie du Solide, De ´partement de Chimie, Faculte´ des Sciences de Monastir, 5019 Monastir, Tunisia article info Article history: Received 14 May 2012 Received in revised form 12 August 2012 Accepted 19 August 2012 Available online 7 September 2012 Keywords: Sn(II) Halide and pseudo halide Structure Indirect spin-spin coupling Dielectric properties Electrical conductivity abstract Synthesis, structural and electrical properties are given for a new organic stannous pseudo halide material. The structure of the [C 2 H 10 N 2 ][(SnCl(NCS) 2 ] 2 reveals that the adjacent Sn(II) centres are bridged by a pair of SCN  anions to form  a 1-D array giving rise to the anionic chains (SnCl(NCS) 2 ) n n  . These chains are themselves interconnected by means of N–HyCl(S) hydrogen bonds originating from the organic cation [(NH 3 ) 2 (CH 2 ) 2 ] 2 þ . The AC impedance measurements were performed as a function of both frequency and temperature. The electrical conduction and dielectric relaxation have been studied. The activation energy associated with the electrical relaxation determined from the electric modulus spectra was found close to that of the activation energy obtained for DC conductivity. The conduction mechanisms are attributed to the quantum mechanical tunneling model in phase I and to the proton hopping among hydrogen vacancies in phase II. & 2012 Elsevier Inc. All rights reserved. 1. Introduction The field of crystal engineering of new crystalline architectures has gradually outlined the promising perspective to attain the purposive design and synthesis of a novel quality of nonlinear optical (NLO) materials with high electric polarisability due to the presence of lone pair’s electron at the Sn(II), cations and the SCN  anions. It is well known that the presence of non-bonding valence electrons on subvalent metal atoms of the p-block elements typically results in stereochemical distortion of the environment around the metal atom and is commonly known as Inert-Pair-Effect. Coordination chemistry of [SnXY2E]- complexes containing halide anions X(F, Br, Cl, I) pseudo halid ion Y(NCS) and LP.E(E), is interesting from the structural point of view because the different coordination modes of the ligands to the metal ions [1]. Thiocyanate and isothiocynate anions can link metal center in end -to- end or in an end -on mode by their terminal S and N-bonding modes respectively. In Sn(II) halides complex, the most common metal coordination environment is a trigonal-pyramidal arrangement of three nearest neighbours with three more distant tin-ligand contacts completing a distorted octahedral environment. Hybrid organic– inorganic materials offer scientifically and technologically significant opportunities for combining attractive features of inorganic and organic systems within a single crystal. The organic portion is usually an organic ammonium cation, balancing the negative charge from the inorganic layer. The inorganic moiety offers potential advantages such us electrical mobility, thermal stabilityy Many of these compounds exhibit structural dielectric transitions, which are associated with the reorientational dynamics of the ammonium group and the hopping mechanism, dominated by the motion of the H þ ions via the hydrogen bonds [2–4]. In the present work we describe the crystal structure of ethylenediammonium bis chloro diisothiocyanato stannate(II); (hereafter abbreviated to EBCTS). Detailed calorimetric, solid CP-MAS 13 C NMR characterization, and A.C-DC conductivity and dielectric studies, through impedance mea- surements are given. 2. Experimental details 2.1. Crystal chemistry Crystals of EBCTS were obtained by dissolving in HNO 3 (0.5 M) solution a stoichiometric mixture of Sn(SCN) 2 obtained by the Filby method [5] and, dichloro ethylenediammonium according to the following chemical reaction. C 2 H 10 N 2 Cl 2 þ 2 SnðSCNÞ 2  HNO 3  ! Sn C 2 H 10 N 2 ðSnClðNCSÞ 2 Þ 2 Metallic tin was added to the obtained solution to avoid the oxidation of Sn(II) to Sn(IV). This solution was then put in desiccators over CaCl 2 . After several days parallelipipedic- shaped monocrystals of [C 2 H 10 N 2 ][SnCl(NCS) 2 ] 2 appeared in the solution. They were washed with diethyl ether and dried over P 2 O 5 . The EBCTS salt crystallizes in the monoclinic P2 1 /n system with the following unit cell dimensions: a ¼ 5.694(10) ˚ A, b ¼ 19.886(7) ˚ A, c ¼ 8.2591(10) ˚ A, b ¼ 108.758(10)1. The unit cell Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/jssc Journal of Solid State Chemistry 0022-4596/$ - see front matter & 2012 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jssc.2012.08.040 n Corresponding author. Fax: þ216 74669330. E-mail address: slah.kamoun@gmail.com (S. Kamoun). Journal of Solid State Chemistry 197 (2013) 60–68