Ferroelectric and ferroelastic properties of Rb2MnCl4•2H2O

Rb2MnCl4 center dot 2H(2)O crystal belonging to the family of tetrahalogeno-metallates dihydrates has been subjected to thermal, optical and dielectric studies. At room temperature the optical study under a polarization microscope has revealed a ferroelastic domain structure. At 240 K a dielectric anomaly, characteristic of the week ferroelectric phase transition, has been also observed. Moreover, below the temperatures of the phase transitions dielectric dispersion has appeared. Ferroic properties of Rb2MnCl4 center dot 2H(2)O crystal have been compared to those of other tetrachlorides dehydrates.