Structural, thermal and dielectric studies on the novel solution grown (4-dimethylaminopyridinium) chloroantimonate(III) and chlorobismuthate(III) crystals

The single crystals of the following 4-dimethylaminopyridinium chloroantimonates(III) and chlorobismuthates(III) have been grown by the solvent evaporation method: (C7H11N2)SbCl4, (C7H11N2)BiCl4 and (C7H11N2)4Bi2Cl10(C7H11N2)4Bi2Cl10. The one-dimensional (1D) structures for (C7H11N2)SbCl4 or (C7H11N2)BiCl4 and the zero-dimensional (0D) one for (C7H11N2)4Bi2Cl10(C7H11N2)4Bi2Cl10 have been solved by the single-crystal X-ray diffraction method. (C7H11N2)SbCl4 and (C7H11N2)BiCl4 appeared to be isomorphous and crystallize in the monoclinic space group, C2/c  , whereas (C7H11N2)4Bi2Cl10(C7H11N2)4Bi2Cl10 in the orthorhombic one, Imma. The molecular arrangements in the subsequent crystal lattices have been studied. For all three compounds by using the differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) no structural phase transition has been detected in temperature region between 100 and 400 K. Nevertheless, the dielectric relaxation processes in temperature region 100–450 K and frequency range between 100 Hz and 2 MHz have been found in all crystals studied. The experimental results of the real and imaginary parts of the dielectric permittivity allow us to estimate the parameters of the relaxation processes, i.e. macroscopic relaxation times, τ, and activation energies, EA. The dynamics of the dipolar organic cations is expected to contribute to the relaxations process in the crystals under investigation.

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► The one-dimensional (1D) and the zero-dimensional (0D) anionic structure.
► The ‘crystal bending’ discovered in RMX4-type analogue.
► The low frequency relaxation processes attributed to the dynamics of the organic cations.