Crystal Structure, Thermal Behaviour and Vibrational Spectra of Tetraethylammonium Dihydrogenmonophosphate Bis Phosphoric Acid

摘要

Single crystals of the tetraethylammonium dihydrogenmonophosphate bis trihydrogenmonophosphate [CH3CH2]4N+(H2PO4)(H3PO4)2(TEP), were grown by slow evaporation solution technique at room temperature. The compound was characterised by IR, Raman, differential thermal analysis (TG-DTA) and single crystal X-ray diffraction. It crystallizes in the monoclinic system (space group P21/c) with the following unit cell dimensions: a = 7.765 (2) , b = 16.531 (4) , c = 14.843 (2) , β = 100.99 (2)o, Z=4 , DX =1.67Mg.m-3, Dm=1.532Mg-3, λ (MoKa) = 0.71073 , u=0.384 mm-1, F(000)=991, T = 20 (2)o. The structure was solved by the direct method and refined to final R value of 0.0342 and Rw=0.107 for 3239 independent [(CH3CH2)4N]+ reflections. The structure consists of infinite parallel two-dimensional planes built of mutually , H3PO4 tetrahedra ?and cations connected by strong and hydrogen bonding. There are no contacts other than van der Waals interactions between the layers.