【摘要】 <正> 硫氰酸铁的比色法是早已熟知的课题。业已确认,在水溶液中,铁(Ⅲ)与硫氰酸根生成最大配位数为6的六种络合物。各络合物呈现分级解离的现象,热力学稳定性较小,因而限制了它在分析化学上的应用。1978年,林谦次郎等报道了在非离子表面活性剂TritonX-100存在下的增敏作用,在波长485nm时测定有色络合物的摩尔消光系数为1.88×10~4,但对其机理未作详细讨论。在低介电常数的介质中,提高了络合物的热力学稳定性,改变了其各级络合物摩尔消光系数的分配,是可能的原因之一。但迄今文更多还原

【Abstract】 In this paper, the stability constants and molar extinction coefficients of the Fe（SCN）_n^3-n complexes （n=1～6） in the 25% alcohol （v/v） solution and at 0℃ have been determined by the modified Yatsimirskii’s method.Their values are as follows: β₁=49.3, β₂=97.6, β₃=9.13×10³, β₄=9.57×10⁴, β₅=2.70×10⁶ and β₆= 3.69×10⁷ for stability constants; Δ∈₁=4.46×10³, Δ∈₂=8.96×10³, Δ∈₃=1.32×10⁴, Δ∈₄=4.12×10³,Δ∈₅=3.73×10³ and Δ∈₆=1.25×10⁴ for molar extinction coefficients.When the contribution by each of the stepwise stability constants and molar extinction coefficients of the complexes in solution was considered, the experimental results were more satisfactorily explained. The calculated values of the average molar extinction coefficient were compared with the experimental values and found to be in fairly good agreement.更多还原