Synthesis and characterization of dihydroxylammonium tetrachlorocuprate dihydrate crystals by G. Amirthaganesan, M. A. Kandhaswamy, and V. Srinivasan

Crystal Research and Technology

Cryst. Res. Technol. 40, 593 (2005) - Abstract -

Synthesis and characterization of dihydroxylammonium tetrachlorocuprate dihydrate crystals

G. Amirthaganesan, M. A. Kandhaswamy, and V. Srinivasan

Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore-641020, India

Keywords	differntial scanning calorimetry(DSC), phase transition, thermogravimetric analysis(TGA), X-ray diffraction, infrared spectroscopy
PACS	65.40.-b, 61.44. Fw, 61.10.Nz
DOI	10.1002/crat.200410388

A new hydroxylammonium compound, [(NH₃OH)₂CuCl₄], was synthesized and its crystals were grown at room temperature by slow evaporation of aqueous solutions. The crystals were characterized through powder XRD, thermogravimetry (TG), differential thermal analysis (DTA), low temperature differential scanning calorimetric (DSC) and FTIR spectra. The X-ray powder diffraction confirms the crystallinity of the compound. A fitting decomposition pattern of the compound was formulated based on the TG and thereby confirming the formation of the compound in the stoichiometric ratio. The thermal anomalies occurring in the low temperature DSC indicate successive phase transitions. The low temperature phase transitions are attributed to the ordering of [NH₃OH]⁺ ions. While most of the phase transitions are of first order type, the one occurring at -126°C is of second order. Two glass transitions occur when the compound was cooled between -157.9 and -136.9°C. The characteristic vibration bands due to [NH₃OH]⁺ and CuCl₄^2- ions are observed in the IR spectra.

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