Chemistry Department, College of Science, University of Mosul, Mosul-Iraq Manuscript received 2 April 1985, accepted 31 July 1985 Some new mixed ligand complexes of nickel(II) having the compositions Ni(RXan)2 Ni(RXan)2, L2 and Ni(RXan)2 L', where RXan -2-methoxyethylxanthate and 2-ethoxy��ethyl xanthate ; L pyridine, ��-picoline, \(\gamma\) picoline, 3,5-lutidine, 3,5-dichloropyridine or isoquinoline ; and L' -1,10-phenanthroline, 2,2'-iminodipyridine or 2,2'-dipyridyl have been synthesised and characterised on the basis of elemental analysis, magnetic susceptibi��lity, infrared and electronic spectral studies. The free base complexes are diamagnetic, while the base adducts and the tris(xanthato) complexes are paramagnetic with distorted octahedral structures. Relevant ligand field parameters have been calculated for the six-coordinated complexes.