Abstract：The present paper reports the possible geometries and vibrational spectra of AsF-6 anion and M+AsF-6(M+=Li+, Na+, K+, Rb+ and Cs+) contact ion pairs. It was shown that the tridentate C3V structure of M+AsF-6 was preferred over the monodentate and bidentate geometry. In the tridentate structure, the symmetry of AsF-6 in the coordination is lowered because of the presence of M+, and its structural parameters and vibrational modes largely differ from its original octahedral structure. The effect of Li+ on the structure of AsF-6 was greater due to its larger charge/radius ratio. The calculated bands for AsF-6 in M+AsF-6, located in the range of 600-800 cm-1, could be used to fingerprint what kind of ion pair was present in solutions.
Key words：Contact ion pair;Hexafluoroarsenate;Vibrational spectra;ab initio calculation
轩小朋,王键吉*,赵培正. M+AsF-6 (M=Li, Na, K, Rb和Cs)离子对的结构和振动光谱[J]. 光谱学与光谱分析, 2008, 28(12): 2890-2894.
XUAN Xiao-peng, WANG Jian-ji*, ZHAO Pei-zheng. Theoretical Study on Structure and Vibrational Spectra of M+AsF-6 (M=Li, Na, K, Rb and Cs) Contact Ion Pairs. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2008, 28(12): 2890-2894.
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