Synthesis, Crystal Structure and Phase Transition in a Perovskite type (CH3NH3)2M(X)2(Y)2(M=Sn; X=SCN; Y=Cl)

• XRD, FT-IR spectroscopy, DSC and Dielectric study of (CH 3 NH 3 ) 2 Sn(SCN) 2 Cl 2 . • (CH 3 NH 3 ) 2 Sn(SCN) 2 Cl 2 is a ferroelectric relaxor material at T<355 K • (CH 3 NH 3 ) 2 Sn(SCN) 2 Cl 2 exhibits a ferro-paraelectric phase transition at 355 K. The exploration of ferroelectric hybrid materials is highly appealing due to their great technological significance. In line with this, we herein report the development of a new ferroelectric relaxor: (CH 3 NH 3 ) 2 Sn(SCN) 2 Cl 2 was synthesized and studied by single-crystal X-ray diffraction, powder XRD, Differential scanning calorimetry (DSC), IR spectroscopy and dielectric measurements. The phase purity was confirmed by Rietveld refinement of the X-ray powder diffraction pattern. It crystallizes, at room temperature, in the orthorhombic system with the Pnm2 1 space group. The crystal structure is formed of discrete ionic entities (CH 3 NH 3 ) + and (Sn(SCN) 2 Cl 2 ) 2- . The methylammonium cations are bonded to these chains by hydrogen-bonding contacts. DSC measurement shows that this compound exhibits a diffuse ferro–paraelectric phase transition around 355 K. Dielectric study exhibits a relaxor behavior characterized by the transition temperature shifts toward higher temperature with the rise of frequency. This behavior was validated by the modified Curie–Weiss law. The diffuseness parameter was the γ is approach to 1.96 at 2000 KHz. Graphical Abstract Legend Crystal structure, dielectric relaxation and phase transition in a Perovskite type (CH 3 NH 3 ) 2 M(X) 2 (Y) 2 (M=Sn; X=SCN; Y=Cl)