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

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