Crystal structure and electrical conduction mechanism of the new bi-tetrabutylphosphonium hexachlorostannate compound

Abstract

The bi-tetrabutylphosphonium hexachlorostannate [P(C4H9)4]2SnCl6 compound is a new member of the family of organic-inorganic hybrid like perovskite system. This compound crystallizes in the monoclinic space group C2/c with unit cell parameters a = 14.4008 Å, b = 18.7256 Å, c = 17.5135 Å and β=113.1780° The (SnCl6)2− anions are surrounded by six [(C4H9)P]+ cations, forming an octahedral configuration. Regarding the differential scanning calorimetry, three order- disorder reversible phase transitions were observed at T1 = 388/363 K, T2 = 403/395 K and T3 = 446/410 K. Analysis of frequency and temperature dependence of impedance and electrical modulus spectroscopic data and Nyquist plots has shown the contributions of grains and grain boundaries to the electrical properties of the prepared material. The variation of the dielectric loss log (ε ‘’) with log (ω) is found to follow the empirical law, ε’’= Bωm(T). Moreover, the temperature dependence study of frequency exponent m (T) is investigated toexplain the conduction mechanism in the different parts, which is attributed to the non overlapping small polaron tunneling (NSPT) in the region I, II and III and by the correlated barrier hopping (CBH) model in phase IV.