Synthesis and characterization of the layered K2NiF4 type (CnH2n+1NH3)(2)PbCl4 system

Layered K2NiF4-type (CnH2n+NH3)(2)PbCl4(n=6, 8 and 10) system, or alkylammo nium tetrachloroplumbate compound, has been synthesized from PbCl2 and CnH2 n+1NH3Cl solutions under argon ambient pressure for 12hrs at 90 degrees C. The crystal structure of the compound has been analyzed using X-ray powder diffraction in the range of 5 degrees less than or equal to 2 theta less th an or equal to 55 degrees, and all samples assigned to an orthorhombic syst em. Local distances of the Pb-Cl bond have been determined by Pb L-III-edge extended X-ray absorption fine structure (EXAFS) spectroscopy. The vibrati on modes of alkylammonium chains and the absorption peaks of an exciton hav e been examined by FTIR and UV-Vis. reflectance spectra, respectively. The phase transition temperatures of the compounds have been studied by using D SC. According to the thermal analysis, two phase transition temperatures ha ve been observed in the compositions of n=8 and 10.