Crystal structure, vibrational and spectroscopic study of single crystal (C6H15N4O2)H2PO4.H2O

Abstract

A single crystal was selected from the reaction product of a stoichiometric mixture of phosphoric acid (H₃PO₄) to which was added the L-arginine (C₆H₁₄N₄O₂) and its crystal structure was determined from three dimensional X-ray diffraction data. The structure is monoclinic, space group P2₁, a = 7.3450(14) Å, b = 7.9176(15) Å, c = 10.8796(22) Å, β = 97.98(2)°,
V = 626.57(186) Å³ and Z = 2, least squares refinement was converged to R₁=0.0456, wR₂=0.1433 for 3278 unique reflections. The structure consists of chains formed by edge sharing of PO₄ tetrahedra, water and arginine. The stacking along b axis consists of these chains bridged by layers formed by PO₄ water and arginine by hydrogen bonds. The Raman and infrared spectra of single crystal LAP were recorded to determine the symmetries of the vibrations of the various molecular groups such as NH₃⁺, NH₂, CH₂, CH, COO^-, H₂O and H₂PO₄ present in the crystal.