Chromium(III) Compounds with Some Organic Ligands

The equilibrium acquisition times in chromium(III)-organic ligand systems were determined under various conditions. Chromium(III) compounds with picolinic acid Cr(C6H4NO2)(3) . H2O, nicotinic acid CrOH(C6H4NO2)(2) . 2H(2)O, and citric acid CrC6H5O7 . 3H(2)O were isolated; their gravimetric and thermogravimetric analyses carried out; and IR spectra measured. The major chromium(III) complex species with the above-listed acid anions in solutions were found to have a (1 : 1) stoichiometry using isomolar series; their stability constants were determined by potentiometric measurements. The electronic absorption spectra of the systems were analyzed. The photometric determination of chromium picolinate in solutions was developed, the solubility constant K-S was determined (log K-S = -21.52 +/- 0.29), quantum-chemical calculations carried out for a gaseous molecule, and energy and geometric parameters calculated.