Force constant calculations for tetrakis(tribromophosphine)nickel(0), Ni(PBr 3) 4

Abstract

Force constant calculations have been carried out for Ni(PBr 3) 4 using a simple valence force field with interaction constants. The force constant values are compared for the coordinated and free ligand and also with k(NiP) stretching in the series of molecules Ni(PX 3) 4 where X=F, Cl, Me. The k(NiP) stretching force constant in Ni(PBr 3) 4 is much lower than its corresponding values for other members of the series. This is discussed in relation to the observed experimental instability of the compound and the electronegativities of the substituents X in PX 3.