Synthesis, crystal structure and phase transition in a perovskite type (CH3NH3)2M(X)2(Y)2(M=Sn; X=SCN; Y=Cl)

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: (CH3NH3)(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 (CH3NH3)(+) 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 gamma is approach to 1.96 at 2000 KHz. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this study, a new ferroelectric relaxor (CH3NH3)(2)Sn(SCN)(2)Cl-2 was synthesized and characterized using single-crystal X-ray diffraction, powder XRD, DSC, IR spectroscopy, and dielectric measurements. The compound exhibited a diffuse ferro-paraelectric phase transition around 355 K and showed relaxor behavior with the transition temperature shifting towards higher temperatures with increasing frequency. The crystal structure consists of discrete ionic entities and methylammonium cations bonded through hydrogen-bonding contacts.