Complexity in "simple" electrolyte solutions:: Ion pairing in MgSO4(aq)
Complexity in "simple" electrolyte solutions:: Ion pairing in MgSO4(aq)
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DOI：
10.1021/jp034870p
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发表时间：
2004-02-19
影响因子：
3.3
通讯作者：
Hefter, G
中科院分区：
文献类型：
--
作者：
Buchner, R;Chen, T;Hefter, G
用介电弛豫谱对MgSO_4水溶液在宽的频率（0.2 ≤ v/GHz ≤ 89）和浓度（0.017 ≤ c/M ≤ 2.24）范围内进行了详细的研究。详细的光谱分析表明，结论性的，长期以来一直推断从超声波吸收研究，同时存在的双溶剂分离（2SIP），溶剂共享（SIP），和接触（CIP）离子对。每个离子对类型的逐步形成和整体协会的常数与文献估计基于其他种类的测量是非常一致的。此外，已经获得了在高电解质浓度（c > 1 M）下存在三重离子Mg 2SO 42+（aq）或可能更聚集的物质的证据。通过拉曼光谱提供了CIP、SIP和三重离子存在的支持。本研究结果的影响，高价电解质的热力学行为的定量模型进行了简要讨论。
A detailed investigation of aqueous solutions Of MgSO4 has been made by dielectric relaxation spectroscopy over a wide range of frequencies (0.2 less than or equal to v/GHz less than or equal to 89) and concentrations (0.017 less than or equal to c/M less than or equal to 2.24). Detailed analysis of the spectra shows conclusively, as has long been inferred from ultrasonic absorption studies, the simultaneous presence of double solvent separated (2SIP), solvent-shared (SIP), and contact (CIP) ion pairs. The constants derived for the stepwise formation of each ion pair type and for the overall association are in excellent agreement with literature estimates based on other kinds of measurements. In addition, evidence has been obtained for the existence of a triple ion, Mg2SO42+(aq), or possibly a more aggregated species, at high electrolyte concentrations (c > 1 M). Support for the presence of CIPs, SIPs, and the triple ion is provided by Raman spectroscopy. The implications of the present findings for quantitative models of the thermodynamic behavior of higher-valent electrolytes are briefly discussed.