Synthesis, crystal structure, IR, Raman-spectroscopy and DFT computation of monostrontium phosphate monohydrate, Sr(H<sub>2</sub>PO<sub>4</sub>)<sub>2</sub>·H<sub>2</sub>O
Smail El Makhloufy, El Mehdi Majdi, A. Ouasri, Samir Chtita, Mohamed Saadi, Lahcen El Ammari, Abdelouahed Cherqaoui, Saïd Belaaouad
Abstract
The compound Sr(H2PO4)2·H2O has been synthesized and studied by single crystal X-ray diffraction analysis, infrared and Raman vibrational spectroscopy and density functional theory calculations. This compound crystallizes in the triclinic centrosymmetric space group P-1(Z = 2) with a = 5.7641(4) Å, b = 6.4549(4) Å, c = 12.0746(9) Å, α = 93.386(2)°, β = 95.730(2)° and γ = 114.114(2)°. The three-dimensional structure contains Sr(H2PO4)+ chains, which form corrugated layers. Between these layers are placed layers of (H2PO4)- ions and water molecules. The bands observed in the infrared and Raman spectra of Sr(H2PO4)2·H2O are assigned based on the results obtained in the literature and upon theoretical group analyses made in the factor group Ci. The optimal molecular geometry, harmonic vibrational frequencies, infrared intensities and Raman scattering activities were calculated by using density function theory (DFT/B3LYP) methods with the LanL2DZ basis set. The HOMO-LUMO properties and geometries of this compound have been determined and discussed. The computational structural parameters are generally in agreement with the experimental investigations. The theoretical infrared and Raman spectra for the title compound have been constructed.