Application of X-ray photoelectron spectroscopy for studying the molecular structure of corrosion inhibitor — Zinc complex of 1-hydroxyethylidene diphosphonic acid

Abstract

The molecular structure of zinc complex of 1-hydroxyethylidene diphosphonic acid was studied by X-ray photoelectron spectroscopy. The obtained data were compared with IR absorption spectrum of the same substance to acquire new information on the molecular structure. It was shown that coordination of the phosphonate group by zinc atom retains the localization of P-O π bond, the phosphonate group does not have a third-order axis of symmetry, and Zn atom can occupy positions with different coordination. Thermal destruction of the complex is accompanied by decomposition of hetero-organic ligand with detachment of the hydrocarbon fragment along C-P bonds and formation of inorganic zinc salts.