title: Analysis of cationic structure in some room-temperature molten fluorides and dependence of their ionic conductivity and viscosity on hydrofluoric acid concentration.
abstract: To understand the ionic and nonionic species in (CH(3))(4)NF·mHF, (CH(3))(3)N·mHF, (C(2)H(5))(4)NF·mHF, and (C(2)H(5))(3)N·mHF melts, the structures of these melts were investigated by infrared spectroscopy, NMR, and high-energy X-ray diffraction. Infrared spectra revealed that three kinds of fluorohydrogenate anions, (FH)(n)F(-) (n = 1, 2, and 3), and molecular hydrofluoric acid (HF) are present in every melt. Ionic conductivity and viscosity of these melts were measured and correlated with their cationic structure. The ionic conductivity of the R(4)N(+)-systems was higher than that of corresponding R(3)NH(+)-systems because a strong N-H···F(HF)(n) interaction prevents the motion of R(3)NH(+) cations in the R(3)N·mHF melts. (CH(3))(4)N(+) and (CH(3))(3)NH(+) cations gave higher ionic conductivity than (C(2)H(5))(4)N(+) and (C(2)H(5))(3)NH(+) cations, respectively, because the ionic radii of former cations were smaller than those of latter. It was concluded that these effects on ionic conductivity can be explained by the cationic structure and the concentration of molecular HF in the melts.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Doshisha University, 1-3 Miyako-dani, Tatara, Kyotanabe, Kyoto 610-0321, Japan. tomohiro.isogai@daikin.co.jp
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Isogai
authors.forename: Takaaki
authors.initials: T
authors.lastname: Nakai
authors.forename: Hidemi
authors.initials: H
authors.lastname: Inoue
authors.forename: Kenta
authors.initials: K
authors.lastname: Nakanishi
authors.forename: Shinji
authors.initials: S
authors.lastname: Kohara
authors.forename: Morihiro
authors.initials: M
authors.lastname: Saito
authors.forename: Minoru
authors.initials: M
authors.lastname: Inaba
authors.forename: Akimasa
authors.initials: A
authors.lastname: Tasaka