Synthesis and thermal, phase transition and FTIR spectral characterization of tetraethylammonium tetrachlorocuprate (II) crystals

✍ Scribed by G. Amirthaganesan; M. A. Kandhaswamy

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 136 KB
• Volume: 42
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/crat.200710905

✦ Synopsis

Single crystals of tetraethylammonium tetrachlorocuprate (II), [N(C 2 H 5 ) 4 ] 2 CuCl 4 , were grown by slow evaporation method at room temperature. The crystals were characterized through powder XRD, thermogravimetric (TG-DTA), low temperature differential scanning calorimetric (DSC) studies and FTIR spectroscopy. While the powder XRD pattern of the compound shows sharp Bragg peaks confirming the crystallinity of the compound, the TG-DTA studies confirm formation of the compound in the stoichiometric ratio. The thermal anomalies observed in DSC curve at -120ºC in the heating cycle and around -30ºC in the cooling cycle indicate a first order phase transition. The phase transition was predicted to be associated with the ordering of CuCl 4 2-and successive long range orientation of [N(C 2 H 5 ) 4 ] + ions which are disordered at high temperatures. The cationic [N(C 2 H 5 ) 4 ] + plays a role in phase transitions at low temperatures. The sharp exothermic peak observed in high temperature DSC indicates a structural phase transition when [N(C 2 H 5 ) 4 ]CuCl 3 is formed on heating the compound. The FTIR spectra of the compound characterize the various chemical bonding and water molecules adsorbed in the compound.