ANALYSIS ON CORRELATION BETWEEN STRUCTURE OF SPECIES IN ROOM-TEMPERATURE MOLTEN SALTAND MECHANISM OF ELECTRODE REACTION

(CH_3)_4NF·mHF(m=3~5)and(CH_3)_4NF·mDF(m=3.0，3.5，4.0)melts were prepared by reaction of(CH_3)_4NF with HF and DE respectively.Analysis of high-energy X-ray diffraction of(CH_3)_4NF·mHF and NH_4F·nHF melts indicated that(CH_3)_4NF·mHF melts had the intermolecular correlations of the(CH_3)_4N^+cation in liquid state and hence the tetrahedral NC_4short-range structure was maintained.Comparison of the measured Raman and IR spectra of(CH_3)_4NF·mHF melts with ab initio calculation revealed that a HF molecule in addition to(FH)F^-，(FT)_2F^-，and(FD)_3F^-existed in the melts and that(FH)_2F^-was the most species among them having HF.The frequencies observed in Raman and IR spectra of(CH_3)_4NF·mDF melts were compared with ab initio calculation.Consequently，it is confirmed that(FD)F^-，(FD)_2F^-，and(FD)_3F^-also existed in the melts.Electrolytic conductivity of(CH_3)_4NF·mHF melts increased with increasing m value，whereas their viscosity decreased with the increase of m value，because the concentration of HF molecule in the melts increased with increasing m value.In electrolysis of(CH_3)_4NF·mHF melts containing CsF with a nickel anode，the best ratio of(CF_3)_3N to the overall anode gas was 40.5%.In electrolysis of only(CH_3)_4NF·mHF melts with the LiNiO_2 and the LaNiO_3coated Ni sheet anodes prepared by atmosphere plasma spraying technique and sol-gel method，an insulating NiF_2was prevented from formation in the surface layer on the anodes and resistance of the surface layer was decreased.The best ratio of(CF_3)_3N to the overall anode gas on the LiNiO_2coated Ni sheet anode prepared by atmosphere plasma spraying technique was 33.1%.Those on the LiNiO_2 and the LaNiO_3coated Ni sheet anodes prepared by sol-gel method were 27%and 25%，respectively。

(CH_3)_4NF・mHF (m=3〜5) and (CH_3)_4NF・mDF (m=3.0, 3.5, 4.0) melts were prepared by reaction of (CH_3)_4NF with HF and DE respectively. Analysis of high-energy X-ray diffraction of (CH_3)_4NF・mHF and NH_4F・nHF melts indicated that (CH_3)_4NF・mHF melts had the intermolecular correlations of the (CH_3)_4N^+ cation in liquid state and hence the tetrahedral NC_4 short-range structure was maintained. Comparison of the measured Raman and IR spectra of (CH_3)_4NF・mHF melts with ab initio calculation revealed that a HF molecule in addition to (FH)F^-, (FT)_2F^-, and (FD)_3F^- existed in the melts and that (FH)_2F^- was the most species among them having HF. The frequencies observed in Raman and IR spectra of (CH_3)_4NF・mDF melts were compared with ab initio calculation. Consequently, it is confirmed that (FD)F^-, (FD)_2F^-, and (FD)_3F^- also existed in the melts. Electrolytic conductivity of (CH_3)_4NF・mHF melts increased with increasing m value, whereas their viscosity decreased with the increase of m value, because the concentration of HF molecule in the melts increased with increasing m value. In electrolysis of (CH_3)_4NF・mHF melts containing CsF with a nickel anode, the best ratio of (CF_3)_3N to the overall anode gas was 40.5%. In electrolysis of only (CH_3)_4NF・mHF melts with the LiNiO_2 and the LaNiO_3 coated Ni sheet anodes prepared by atmosphere plasma spraying technique and sol-gel method, an insulating NiF_2 was prevented from formation in the surface layer on the anodes and resistance of the surface layer was decreased. The best ratio of (CF_3)_3N to the overall anode gas on the LiNiO_2 coated Ni sheet anode prepared by atmosphere plasma spraying technique was 33.1%. Those on the LiNiO_2 and the LaNiO_3 coated Ni sheet anodes prepared by sol-gel method were 27% and 25%, respectively.