Schrödle Simon, Wachter Wolfgang, Buchner Richard, Hefter Glenn
Chemistry Department, Murdoch University, Murdoch, WA 6150, Australia.
Inorg Chem. 2008 Oct 6;47(19):8619-28. doi: 10.1021/ic702396r. Epub 2008 Aug 29.
Ion association in aqueous solutions of scandium sulfate has been investigated at 25 degrees C and at concentrations from 0.01 to 0.8 M by broadband dielectric spectroscopy over the frequency range 0.2 <or= nu/GHz <or= 89. Detailed analysis of the spectra reveals the presence of both inner- and outer-sphere 1:1 [ScSO 4] (+)(aq) complexes, similar to solutions of other high-valent metal sulfates. Outer-outer-sphere 1:1 complexes are probably also formed, but their contribution is swamped by the presence of higher-order inner-sphere complexes. The latter predominate in the more concentrated solutions, causing major changes to the low-frequency end of the spectrum. The data, while not definitive, are consistent with fac-[Sc(SO 4) 3(OH 2) 3] (3-) as the major species present. The speciation is strikingly different from that recently reported for aluminum sulfate solutions and indicates that the often-postulated similarity between the aqueous chemistry of Al(III) and Sc(III) has to be treated with caution.
通过宽带介电谱在0.2≤ν/GHz≤89的频率范围内，研究了25℃下硫酸钪水溶液中离子缔合情况，浓度范围为0.01至0.8M。对光谱的详细分析表明，存在内球和外球1:1 ScSO₄(aq)络合物，这与其他高价金属硫酸盐溶液类似。外-外球1:1络合物可能也会形成，但其贡献被高阶内球络合物的存在所掩盖。后者在浓度较高的溶液中占主导，导致光谱低频端发生重大变化。这些数据虽不确凿，但与fac-Sc(SO₄)₃(OH₂)₃作为主要存在物种相符。其物种形成与最近报道的硫酸铝溶液显著不同，表明通常假定的Al(III)和Sc(III)水化学之间的相似性必须谨慎对待。
