THE EFFECTS OF ALKALI-METAL IONS AND ALKALINE-EARTH METAL-IONS ON THE ADDUCT FORMATION OF THIOCYANATO-N COBALTATE(II) COMPLEXES WITH NONIONIC SURFACTANT

On adding Triton X-100, a nonionic surfactant, to an aqueous solution of cobalt (II) containing some alkali metal or alkaline earth metal thiocyanates in excess, a deep blue tarry gel deposited. The gels were stoichiometric adducts such as M1/2[Co(NCS)(4)]. 2Triton. or M(II)[Co(NCS)(4)]. 2Triton. These compositions remained essentially constant despite using various concentrations of Triton except barium salt. Counter ion of thiocyanate had a serious effect on gel formation. Lithium, magnesium,and calcium thiocyanates produced no analogous gels, while barium thiocyanate formed non-stoichiometric Triton adduct, which precipitated even without cobalt (II). The yields of such blue gels were observed in the following order: Ba2+ > K+ = Rb+ > Cs+ > NH4+ > Sr2+ > Na+. The recovery of cobalt (II) remaining in the supernatant Liquid was minimized for all counter ions when the initial addition was conducted at a molar ratio of Triton/Co(II) = 2.