Détermination De La Densité De Charges Dans Un Composé Inorganique

Abstract

The work presented in this thesis consists of determining the distribution of electron density of an inorganic compound, the "Zinc Potassium triborate," chemical formula "KZnB3O6", by the method of X-ray diffraction for single crystal in low temperature. For treatments of the raw data we adopted the Blessing formalism while structural resolution is performed using the least squares method. A rigorous description of the structure requires the determination of atomic coordinates of all atoms, to this effect must be referred to respectively bond lengths, valence angles, torsion angles and the parameters of isotropic and anisotropic thermal motion. The stability of the different parameters of confidence in cycles of refinement for judging the validity of the structure factor value. For the best resolution obtained the value of R factor was 1.42%. To judge the value of the previous results, we proceed to calculate all parameters of the structure by two theoretical methods namely the Hartree-Fock and DFT. The results obtained were similar to those deduced from the method of X-ray diffraction In memory of late we have been careful to calculate the electron density of this compound as the Hansen-Coppens model and establish the electron density maps to highlight the electrons contours about chemical bonds.