[Theoretical study on structure and vibrational spectra of M+ AsF6- (M=Li, Na, K, Rb and Cs) contact ion pairs].
The present paper reports the possible geometries and vibrational spectra of AsF6- anion and M+ AsF6- (M+ = Li+, Na+, K+, Rb+ and Cs+) contact ion pairs. It was shown that the tridentate C3v structure of M+ AsF- was preferred over the monodentate and bidentate geometry. In the tridentate structure, the symmetry of AsF6- 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 AsF6- was greater due to its larger charge/radius ratio. The calculated bands for AsF6- in M+ AsF6-, located in the range of 600-800 cm(-1), could be used to fingerprint what kind of ion pair was present in solutions.
Xuan
Xiao-peng
XP
School of Chemical and Environmental Sciences, Henan Normal University, Xinxiang 453007, China. xpxuan@henannu.edu.cn
Wang
Jian-ji
JJ
Zhao
Pei-zheng
PZ