Successive phase transitions in tetra(isopropylamine)decachlorotricadmate (II) [(CH3)2CH NH3]4Cd3Cl10] crystal - Dielectric and dilatometric studies

Single crystal of a new [(CH₃)₂CHNH₃]₄Cd₃Cl₁₀ compound was grown and its properties have been characterized by dielectric and dilatometric investigations. Dielectric measurement evidenced the phase transitions at T₁ = 352.8 K, T₂ = 293.5 K and T₃ = 261.5 K on cooling run. Dilatometric measurement of thermal expansion showed clearly two successive phase transitions at T₁ and at T₂. No temperature hysteresis was observed for phase transitions at T₁ and T₂. Large temperature hysteresis was observed at T₃ in dielectric studies. Transitions at T₁ and T₃ are classified as a first order and at T₂ as a continuous one. Anomalies of electric permittivity and expansion connected with the transitions are observed at practically the same temperatures and close to those observed earlier in DSC (Differential Scanning Calorimetry) studies. Results of dilatometric studies were applied to estimate critical coefficient β for continuous phase transition at T₁ which is equal to 0.40 ± 0.01.