PREPARATION AND APPLICATION OF Cr-Fe TANNING AGENT MADE FROM REDUCTION OF DICHROMATE WITH SHAVINGS CONTAINING CHROME AND FERROUS SULPHATE

摘要

Within the range of visible spectrum, [Cr(H2O)6]~(3+) has obvious absorption and the characteristic absorption peaks appears at 408nm and 575nm. When ligands like SO_4~(2-), Cl~-, organic acid radical complexes with the central ion Cr~(3+), bathochromic shifts will happen to the characteristic peaks; when the ligands form bridge bonds or cyclic structures with the central ion, hypsochromic shifts will happen. Therefore, the spectral absorption curve changes as the inner-sphere ligands are replaced by other ligands or heterdcomplex structures are formed.