Spectral studies of Nickel(II) and Chromium(III) complexes with some organic acids in aqueous solution

Complexes of Cr(III) and Ni(II) ions with phthalate, sulphanilate, antıranillate, hippurale, 8-quinolinolate and glycinale ions have been prepared, absorption spectra of their aqueous solutions at the visible and U.V.region were recorded, then the Nephelauxclic ratio (P) was calculated. Results showed that covalency between metal ions and ligands is largely affected by rk - bonding due to tzy ulectrons, the ligands could be arranged according to their increased tendency for covalent bonding (hig) as follows: H20< sulph