Properties, manipulations, preparative methods and typical reactions have been described for the following twelve representative nickel compounds which have been used and/or should be useful as catalysts and/or reagents for synthetic organic reactions : nickel (II) halides, his (acetylacetonato) -nickel (II), nickel peroxide, dichloro (bipyridyl) nickel (II), dihalobis (trialkylphosphine) nickel (II), dichlorobis (triphenylphosphine) nickel (II), dichloro {1, 3-his (diphenylphosphino) propane} nickel (II), trans-chlorophenylbis (triphenylphosphine) nickel (II), tetracarbonylnickel (0), bis (η- 1, 5-cyclooctadienyl) nickel (0), tetrakis (triphenylphosphine) nickel (0), di-μ-bromobis (1-3-η-allyl) dinickel (II).