Ionic Conductivity and Viscosity of Low Temperature Molten Fluorides Containing HF

Analysis of Cationic Structure in Some Room-Temperature Molten Fluorides and Dependence of Their Ionic Conductivity and Viscosity on Hydrofluoric Acid Concentration

“…In both systems, the position for each absorption band was almost unchanged in every m value as shown in Figure . The absorbance of the band assigned to molecular HF increased with increasing the m value, which suggests that the concentration of molecular HF increases with an increase in the m value, as was observed for the (CH 3 ) 4 NF· m HF and (CH 3 ) 3 N· m HF melts.…”

“…In a previous study, we measured the infrared spectra of (CH 3 ) 4 NF· m HF and (CH 3 ) 3 N· m HF, and reported that (CH 3 ) 4 N + cation, fluorohydrogenate anions (FH) n F – ( n = 1, 2, and 3), and molecular HF are present in the (CH 3 ) 4 NF· m HF melts and that the (CH 3 ) 3 NH + cation, the same fluorohydrogenate anions as those in the (CH 3 ) 4 NF· m HF melts, and molecular HF were also present in the (CH 3 ) 3 N· m HF melts. Furthermore, it is concluded that the concentration of molecular HF in both melts increased with an increase in the m value. , …”

“…In a previous study, it was reported that three types of the fluorohydrogenate anions coordinated with HF, (FH) n F – ( n = 1, 2, and 3), that tetramethylammonium cation, (CH 3 ) 4 N + , and molecular HF are present in the (CH 3 ) 4 NF· m HF melts, and that the concentration of molecular HF in the melts increases with increasing the m value . The concentration of molecular HF in the melts affects many properties, such as ionic conductivity, viscosity, vapor pressure, etc . It has been also reported that these effects of HF concentration can be explained in terms of the concentration change of molecular HF and the resulting change in electrostatic cation–anion interactions.…”

Analysis of the Ionic Conduction Behavior in Some Room Temperature Molten Fluorides

“…The self-diffusion coefficients (D) for cation and anion in each molten fluoride were measured by using 1 H nuclei. Stokes's radius (r) of cations and anions in each molten fluoride were estimated by using Stokes-Einstein equation [1],…”

“…IR spectra were also measured for detecting the anionic species such as (FH) n F -(n = 1~3) and a molecular HF in these melts. The amount of HF molecule increased with increasing the m value (1,2). In the present study, the self-diffusion coefficients of ions in the (CH 3 ) 3 N·mHF and (CH 3 ) 4 NF·mHF melts were measured by pulsed-field gradient spin-echo (PFG) nuclear magnetic resonance (NMR) methods, and Stoke's radius of each ion was estimated by using Stokes-Einstein equation.…”