Subsolidus binary phase diagram of the perovskite type layer materials (n-CnH2n+1NH3)2ZnCl4 (n = 10, 12, 14)

Highlights: → The phase diagrams of C10Zn-C14Zn and C12Zn-C14Zn were established by DTA and XRD. → The intermediate compound and two eutectoid invariants in each phase diagram. → Partial miscibility was observed in phase diagrams. - Abstract: The perovskite type layer materials (n-CnH2n+1NH3)2ZnCl4 (n = 10, 12, 14) were studied and a series of their mixtures were prepared from their absolute ethanol solutions. The low temperature crystal structures of the pure salts are characteristic of the piling of sandwiches in which a two-dimensional macro-anion ZnCl42- is sandwiched between two alkylammonium layers. These layers become conformationally disordered in the high temperature phases. It results in the thermotropic solid-solid phase transitions in the (n-CnH2n+1NH3)2ZnCl4. The subsolidus binary phase diagrams of (n-C10H21NH3)2ZnCl4-(n-C14H29NH3)2ZnCl4 and (n-C12H25NH3)2ZnCl4-(n-C14H29NH3)2ZnCl4 were established by differential thermal analysis (DTA) and X-ray diffraction (XRD). The existence of the intermediate compound and two eutectoid invariants were observed in each phase diagram. There are three noticeable solid solution ranges (α, β, γ) at the left boundary, right boundary and middle of the phase diagram.