Environment of Al3+ Ion and Transsolvation Process in Water–Urea Solutions of Aluminum Chloride

Reaction of aluminum chloride crystalline hydrate AlCl 3 (H 2 O) 6 and urea in solid state and AlCl 3 (H 2 O) 6 –CO(NH 2 ) 2 –H 2 O and AlCl 3 (CO(NH 2 ) 2 ) 6 –H 2 O aqueous solutions has been studied. Analysis of IR spectra of studied samples showed that complete substitution of water molecules in the first coordination sphere of Al 3+ ion by urea molecules occurs at the molar ratio Al : CO(NH 2 ) 2 = 1 : 6 in solid and liquid phase. Computation of structures, IR spectra, and energy parameters for (CO(NH 2 ) 2 ) 2 , CO(NH 2 ) 2 (H 2 O) 2 , CO(NH 2 ) 2 (H 2 O) 4 , , and complexes was performed using DFT (B3LYP-6-31++G(d,p)) method. On the basis of obtained data, competition between water and urea molecules in AlCl 3 (CO(NH 2 ) 2 ) 6 aqueous solutions has been studied and experimental results have been explained.