THE EFFECTS OF ALKALI-METAL IONS AND ALKA LINE-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 th iocyanates in excess, a deep blue tarry gel deposited. The gels were s toichiometric adducts such as M1/2[Co(NCS)(4)]. 2Triton. or M(II)[Co(N CS)(4)]. 2Triton. These compositions remained essentially constant des pite using various concentrations of Triton except barium salt. Counte r ion of thiocyanate had a serious effect on gel formation. Lithium, m agnesium,and calcium thiocyanates produced no analogous gels, while ba rium thiocyanate formed non-stoichiometric Triton adduct, which precip itated even without cobalt (II). The yields of such blue gels were obs erved 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 conducte d at a molar ratio of Triton/Co(II) = 2.