The interaction of ferrous sulphate with phthiocolmonoxime in the metal; ligand ratio of 1:2 leads to the formation of monomeric complex Fe-1 having general formula ML 2 , which is a four co-ordinate compound. It is co-ordinatively unsaturated square planer complex Fe-1 complex, which gives the various adduct Fe-2 to Fe-4. All these chelates are anhydrou s like parent Fe-1. The halogenated products Fe-2 to Fe-4 have ML 2 X 2 type of formulation, where (x = Cl, Br, I) and L = phthox. As Fe-2 to Fe-4 fail to show electrolytic nature, also proves that, the second halogen is not is secondary valency of co-ordination sphere but is in primary valency of co-ordination sphere. It was confirmed from the conductivity measurements carried out for parent as well as the adduct chelates. The non-isothermal TG of the compounds Fe-1 to Fe-4 were carried out in air atmosphere. The incipient decomposition temperatures, which are crude measure of thermal stabili ties for Fe-1 to Fe-4 compounds show the following order, Fe-4 < Fe-2 < Fe-3 < Fe-1 The halogenato adducts Fe-2 to Fe-4 show lower thermal stability as compared to parent compound Fe-1.