Powder x-ray diffraction and Rietveld analysis of (C₂H₅NH₃)₂CuCl₄

Structural properties of the organic-inorganic hybrid (C₂H₅NH₃)₂CuCl₄ (EA₂CuCl₄) have been investigated by means of x-ray powder diffraction and Rietveld analysis. A structural phase transition from Pbca to Aba2 occurs at T₄=240 K, which results in a paraelectric-ferroelectric phase transition. The release of the Jahn-Teller distortion with increasing temperature toward T₄ is revealed by the structural analysis.