Visible and UV absorption spectra of fifteen complexes oc cyclopentyl(phenyl)phosphine-Ni(II), Pd(II), and Pt(II) were reported and their steric-configurations were deduced preliminarily. Moreover, mutual transformation of stereo-configurations of Ni(II)-complexes in solns. was discussed. Owing to the steric effect of the substituents in the phosphines, the Ni(II) complexes of cyclopentyl(phenyl)phosphines containing Ph group show the existence of tetrahedral configuration in solution

Key words: ULTRAVIOLET SPECTROPHOTOMETRY, CHLORIDE, IODIDE, BROMIDE, PLATINUM COMPLEX, TRIPHENYLPHOSPHINE, STERIC EFFECT, NICKEL COMPLEX, STEREOISOMERISM, PHOSPHORUS COMPOUNDS