Coordination states of metal ions in molten salts and their characterization methods

Xin Song; Shaolong Li; Shanshan Liu; Yong Fan; Jilin He; Jianxun Song

doi:10.1007/s12613-023-2608-7

Volume 30 Issue 7

Jul. 2023

Turn off MathJax

Article Contents

Article Navigation > International Journal of Minerals, Metallurgy and Materials > 2023 > 30(7): 1261-1277

Xin Song, Shaolong Li, Shanshan Liu, Yong Fan, Jilin He, and Jianxun Song, Coordination states of metal ions in molten salts and their characterization methods, Int. J. Miner. Metall. Mater., 30(2023), No. 7, pp. 1261-1277. https://doi.org/10.1007/s12613-023-2608-7

Cite this article as:

Xin Song, Shaolong Li, Shanshan Liu, Yong Fan, Jilin He, and Jianxun Song, Coordination states of metal ions in molten salts and their characterization methods, Int. J. Miner. Metall. Mater., 30(2023), No. 7, pp. 1261-1277. https://doi.org/10.1007/s12613-023-2608-7

Citation:

PDF( 2573 KB)

Invited Review

Coordination states of metal ions in molten salts and their characterization methods

+ Author Affiliations

Corresponding author:
Jianxun Song E-mail: jianxun.song@zzu.edu.cn
Received: 4 November 2022; Revised: 4 February 2023; Accepted: 8 February 2023; Available online: 10 February 2023

Abstract

Abstract

The macroscopic characteristics of molten salts are governed by their microstructures. Research on the structures of molten salts provides the foundation for a full understanding of the physicochemical properties of molten salts as well as a deeper analysis of the microscopic electrolysis process in molten salts. Information about the microstructure of matter can be obtained with the help of several speculative and experimental procedures. In this review, the advantages and disadvantages of the various test procedures used to determine the microstructures of molten salts are compared. The typical coordination configurations of metal ions in molten salt systems are also summarized. Furthermore, the impact of temperature, anions, cations, and metal oxides (O²⁻) on the structures of molten salts is discussed in detail. The accuracy and completeness of the information on molten salt structures need to be investigated by the integration of multiple methods and interdisciplinary fields. Information on the microstructure and coordination of molten salts deepens the understanding of the elementary elements of the microstructure of matter. This paper, which is based on the review of the coordination states of metal ions in molten salts, is hoped to inspire researchers to explore the inter-relationship between the microstructure and macroscopic properties of materials.
- coordination structure;
- characterization methods;
- molten salt composition;
- electrolysis

FullText(HTML)

Supplements(0)

References(98)

References

[1]	S.Q. Jiao, M.Y. Wang, and W.L. Song, Editorial for special issue on high-temperature molten salt chemistry and technology, Int. J. Miner. Metall. Mater., 27(2020), No. 12, p. 1569. doi: 10.1007/s12613-020-2225-7
[2]	X.L. Xi, M. Feng, L.W. Zhang, and Z.R. Nie, Applications of molten salt and progress of molten salt electrolysis in secondary metal resource recovery, Int. J. Miner. Metall. Mater., 27(2020), No. 12, p. 1599. doi: 10.1007/s12613-020-2175-0
[3]	V. van Speybroeck, R. Gani, and R.J. Meier, The calculation of thermodynamic properties of molecules, Chem. Soc. Rev., 39(2010), No. 5, p. 1764. doi: 10.1039/b809850f
[4]	W. Jia, Molecular Dynamics Study on Structure and Properties of Molten Salt in Alkali Metal Chloride System [Dissertation], East China University of Science and Technology, Shanghai, 2016, p. 145.
[5]	M.H. Brooker, R.W. Berg, J.H. von Barner, and N.J. Bjerrum, Matrix-isolated $ {\mathrm{A}\mathrm{l}}_{2}{\mathrm{O}\mathrm{F}}_{6}^{2-} $ ion in molten and solid LiF/NaF/KF, Inorg. Chem., 39(2000), No. 21, p. 4725. doi: 10.1021/ic000489x
[6]	Y.J. Jin and Y.B. Ai, The technology of nuclear magnetic resonance and its applications, Phy. Eng., 12(2002), No. 1, p. 47.
[7]	Y. Iwadate, K. Suzuki, N. Onda, et al., Local structure of molten LaCl₃ analyzed by X-ray diffraction and La–L_III absorption-edge XAFS technique, J. Alloys Compd., 408-412(2006), p. 248. doi: 10.1016/j.jallcom.2005.04.037
[8]	C.Y. Wang, X.T. Chen, R. Wei, and Y. Gong, Raman spectroscopic and theoretical study of scandium fluoride and oxyfluoride anions in molten FLiNaK, J. Phys. Chem. B, 124(2020), No. 30, p. 6671. doi: 10.1021/acs.jpcb.0c06021
[9]	V. Dracopoulos, B. Gilbert, and G.N Papatheodorou, Vibrational modes and structure of lanthanide fluoride-potassium fluoride binary melts LnF₃–KF (Ln = La, Ce, Nd, Sm, Dy, Yb), J. Chem. Soc., Faraday Trans., 94(1998), No. 17, p. 2601. doi: 10.1039/a802812e
[10]	N. Ma, J.L. You, L.M. Lu, J. Wang, M. Wang, and S.M. Wan, Micro-structure studies of the molten binary K₃AlF₆–Al₂O₃ system by in situ high temperature Raman spectroscopy and theoretical simulation, Inorg. Chem. Front., 5(2018), No. 8, p. 1861. doi: 10.1039/C8QI00226F
[11]	F.G. Edwards, J.E. Enderby, R.A. Howe, and D.I. Page, The structure of molten sodium chloride, J. Phys. C Solid State Phys., 8(1975), No. 21, p. 3483. doi: 10.1088/0022-3719/8/21/018
[12]	E.W.J. Mitchell, P.F.J. Poncet, and R.J. Stewart, The ion pair distribution functions in molten rubidium chloride, Philos. Mag., 34(1976), No. 5, p. 721. doi: 10.1080/14786437608222045
[13]	J. Locke, S. Messoloras, R.J. Stewart, R.L. McGreevy, and E.W.J. Mitchell, The structure of molten CsCl, Philos. Mag. B, 51(1985), No. 3, p. 301. doi: 10.1080/13642818508240576
[14]	X.M. Liu, H.H. Sun, X.P. Feng, and N. Zhang, Relationship between the microstructure and reaction performance of aluminosilicate, Int. J. Miner. Metall. Mater., 17(2010), No. 1, p. 108. doi: 10.1007/s12613-010-0119-9
[15]	A.L. Rollet, C. Bessada, A. Rakhmatoulline, et al., In situ high temperature NMR and EXAFS experiments in rare-earth fluoride molten salts, C. R. Chim., 7(2004), No. 12, p. 1135. doi: 10.1016/j.crci.2004.02.021
[16]	A.L. Rollet, E. Veron, and C. Bessada, Fission products behavior in molten fluoride salts: Speciation of La³⁺ and Cs⁺ in melts containing oxide ions, J. Nucl. Mater., 429(2012), No. 1-3, p. 40. doi: 10.1016/j.jnucmat.2012.05.010
[17]	A.L. Rollet and M. Salanne, Studies of the local structures of molten metal halides, Annu. Rep. Prog. Chem., Sect. C: Phys. Chem., 107(2011), p. 88. doi: 10.1039/C1PC90003J
[18]	Y. Okamoto, H. Shiwaku, T. Yaita, S. Suzuki, and M. Gaune-Escard, High-energy EXAFS study of molten GdCl₃ systems, J. Mol. Liq., 187(2013), p. 94. doi: 10.1016/j.molliq.2013.05.018
[19]	Y. Okamoto, XAFS simulation of highly disordered materials, Nucl. Instrum. Methods Phys. Res. Sect. A, 526(2004), No. 3, p. 572. doi: 10.1016/j.nima.2004.02.025
[20]	Y. Okamoto, H. Shiwaku, T. Yaita, H. Narita, and H. Tanida, Local structure of molten LaCl₃ by K-absorption edge XAFS, J. Mol. Struct., 641(2002), No. 1, p. 71. doi: 10.1016/S0022-2860(02)00329-0
[21]	G.D. Zissi, A. Chrissanthopoulos, and G.N. Papatheodorou, Vibrational modes and structure of the LaCl₃–CsCl melts, Vib. Spectrosc., 40(2006), No. 1, p. 110. doi: 10.1016/j.vibspec.2005.07.005
[22]	G. Bontempelli, F. Magno, and S. Daniele, Simple relationship for calculating backward to forward peak-current ratios in cyclic voltammetry, Anal. Chem., 57(1985), No. 7, p. 1503. doi: 10.1021/ac00284a081
[23]	J.J. O'Dea, J. Osteryoung, and R.A. Osteryoung, Theory of square wave voltammetry for kinetic systems, Anal. Chem., 53(1981), No. 4, p. 695. doi: 10.1021/ac00227a028
[24]	F. Lantelme and M. Chemla, Chronoamperometry for the determination of metallic interdiffusion coefficients. Rapid transport processes in the first atomic layers, J. Electroanal. Chem., 396(1995), No. 1-2, p. 203. doi: 10.1016/0022-0728(95)03933-8
[25]	T.J. Zhu, C.Y. Wang, H.Y. Fu, W. Huang, and Y. Gong, Electrochemical and Raman spectroscopic investigations on the speciation and behavior of chromium ions in fluoride doped molten LiCl–KCl, J. Electrochem. Soc., 166(2019), No. 10, p. H463. doi: 10.1149/2.1221910jes
[26]	M.Y. Wu, Dissolution and Electrochemical Reduction of Multivalent Refractory Metal Oxides in NaKClF Molten Salt [Dissertation], North China University of Science and Technology, Tangshan, 2016, p. 85.
[27]	J. Hetmańczyk, Ł. Hetmańczyk, A. Migdał-Mikuli, and E. Mikuli, Vibrational and reorientational dynamics, crystal structure and solid–solid phase transition studies in [Ca(H₂O)₆]Cl₂ supported by theoretical (DFT) calculations, J. Raman Spectrosc., 47(2016), No. 5, p. 591. doi: 10.1002/jrs.4863
[28]	Y.C. Chen, Principle and application of quantum chemical computation, Technol. Manage. Sci., (2020), p. 110.
[29]	X.J. Li, J. Song, S.P. Shi, et al., Dynamic fluctuation of U³⁺ coordination structure in the molten LiCl–KCl eutectic via first principles molecular dynamics simulations, J. Phys. Chem. A, 121(2017), No. 3, p. 571. doi: 10.1021/acs.jpca.6b10193
[30]	N. Metropolis and S. Ulam, The Monte Carlo method, J. Am. Stat. Assoc., 44(1949), No. 247, p. 335. doi: 10.1080/01621459.1949.10483310
[31]	A. Baranyai, I. Ruff, and R.L. McGreevy, Monte Carlo simulation of the complete set of molten alkali halides, J. Phys. C: Solid State Phys., 19(1986), No. 4, p. 453. doi: 10.1088/0022-3719/19/4/008
[32]	B.J. Alder and T.E. Wainwright, Studies in molecular dynamics. I. General method, J. Chem. Phys., 31(1959), No. 2, p. 459. doi: 10.1063/1.1730376
[33]	C. Bessada, O. Pauvert, D. Zanghi, et al., In situ experimental approach of the speciation in molten lanthanide and actinide fluorides combining NMR, EXAFS and molecular dynamics, ECS Trans., 33(2010), No. 7, p. 361. doi: 10.1149/1.3484794
[34]	C. Bessada, O. Pauvert, L. Maksoud, et al., In situ experimental approach of speciation in molten fluorides: A combination of NMR, EXAFS, and molecular dynamics, [in] M. Gaune-Escard and G.M. Haarberg eds., Molten Salts Chemistry Technololgy, Weley, 2014, p. 219.
[35]	G.D. He, R. Tang, X.Z. Duan, et al., Molecular dynamics study on microstructure and diffusion characteristics of LiF–BeF₂ molten salt, Chem. Eng. J., 71(2020), No. 8, p. 3565.
[36]	H.A. Levy, P.A. Agron, M.A. Bredig, and M.D. Danford, X-ray and neutron diffraction studies of molten alkali halides, Ann. N. Y. Acad. Sci., 79(1960), No. 11, p. 762.
[37]	T. Førland, T. Østvold, J. Krogh-Moe, Monte Carlo studies on fused salts. I. Calculations for a two-dimensional ionic model liquid, Acta Chem. Scand., 22(1968), No. 8, p. 2415.
[38]	M.A. Howe and R.L. McGreevy, A neutron-scattering study of the structure of molten lithium chloride, Philos. Mag. B, 58(1988), No. 5, p. 485. doi: 10.1080/13642818808208460
[39]	R. Takagi, H. Ohno, and K. Furukawa, Structure of molten KCl, J. Chem. Soc., Faraday Trans. 1, 75(1979), art. No. 1477. doi: 10.1039/f19797501477
[40]	C. Kwon, S.H. Noh, H. Chun, I.S. Hwang, and B. Han, First principles computational studies of spontaneous reduction reaction of Eu(III) in eutectic LiCl–KCl molten salt, Int. J. Energy Res., 42(2018), No. 8, p. 2757. doi: 10.1002/er.4064
[41]	J. Zhao, Z.T. Liu, W.S. Liang, and G.M. Lu, Evaluation of the local structure and electrochemical behavior in the LiCl–KCl–SmCl₃ melt, J. Mol. Liq., 363(2022), art. No. 119818. doi: 10.1016/j.molliq.2022.119818
[42]	J. Song, S.P. Shi, X.J. Li, and L.M. Yan, First-principles molecular dynamics modeling of UCl₃ in LiCl–KCl eutectic, J. Mol. Liq., 234(2017), p. 279. doi: 10.1016/j.molliq.2017.03.099
[43]	T. Jiang, N. Wang, C.M. Cheng, S.M. Peng, and L.M. Yan, Molecular dynamics simulation on the structure and thermodynamics of molten LiCl–KCl–CeCl₃, Acta Phys. Chim. Sin., 32(2016), No. 3, p. 647. doi: 10.3866/PKU.WHXB201601042
[44]	G. Pastore, Z. Akdeniz, and M.P. Tosi, Structure of molten yttrium chloride in an ionic model, J. Phys. Condens. Matter, 3(1991), No. 42, p. 8297. doi: 10.1088/0953-8984/3/42/024
[45]	Z. Akdeniz and M.P. Tosi, Structure and binding of ionic clusters in Th and Zr chloride melts, Z. Naturforsch. A: Phys. Sci., 56(2001), No. 11, p. 717. doi: 10.1515/zna-2001-1102
[46]	Y. Okamoto and P.A. Madden, Structural study of molten lanthanum halides by X-ray diffraction and computer simulation techniques, J. Phys. Chem. Solids, 66(2005), No. 2-4, p. 448. doi: 10.1016/j.jpcs.2004.06.038
[47]	Y. Okamoto, S. Suzuki, H. Shiwaku, A. Ikeda-Ohno, T. Yaita, and P.A. Madden, Local coordination about La³⁺ in molten LaCl₃ and its mixtures with alkali chlorides, J. Phys. Chem. A, 114(2010), No. 13, p. 4664. doi: 10.1021/jp910637p
[48]	L. Bulavin, V. Sokol’skii, O. Roik, et al., Structure and physical properties of ternary NaF–LiF–LnF₃ (Ln = La, Nd) systems of eutectic compositions, Phys. Chem. Liq., 54(2016), No. 6, p. 717. doi: 10.1080/00319104.2016.1149176
[49]	H. Cui, Molecular Dynamics Simulation of Melt Structure of Rare Earth Metal Halide Molten Salt System [Dissertation], Kunming University of Science and Technology, 2002, Kumming, p. 136.
[50]	C. Bessada, D. Zanghi, M. Salanne, et al., Investigation of ionic local structure in molten salt fast reactor LiF–ThF₄–UF₄ fuel by EXAFS experiments and molecular dynamics simulations, J. Mol. Liq., 307(2020), art. No. 112927. doi: 10.1016/j.molliq.2020.112927
[51]	A.L Rollet, A. Rakhmatullin, and C. Bessada, Local structure analogy of lanthanide fluoride molten salts, Int. J. Thermophys., 26(2005), No. 4, p. 1115. doi: 10.1007/s10765-005-6688-6
[52]	E. Stefanidaki, G.M. Photiadis, C.G. Kontoyannis, A.F. Vik, and T. Østvold, Oxide solubility and Raman spectra of NdF₃–LiF–KF–MgF₂–Nd₂O₃ melts, J. Chem. Soc., Dalton Trans., 2002, No. 11, p. 2302. doi: 10.1039/b111563b
[53]	G. Hatem and M. Gaune-Escard, Calorimetric investigation of {xKF⁺(1−x)NdF₃}(l), J. Chem. Thermodyn., 25(1993), No. 2, p. 219. doi: 10.1006/jcht.1993.1021
[54]	X.W. Hu, Z.W. Wang, B.L. Gao, Z.N. Shi, F.G. Liu, and X.Z. Cao, Density and ionic structure of NdF₃–LiF melts, J. Rare Earths, 28(2010), No. 4, p. 587. doi: 10.1016/S1002-0721(09)60159-9
[55]	J.X. Dai, H. Han, Q.N. Li, and P. Huai, First-principle investigation of the structure and vibrational spectra of the local structures in LiF–BeF₂ molten salts, J. Mol. Liq., 213(2016), p. 17. doi: 10.1016/j.molliq.2015.10.053
[56]	X.J. Lv, Z.X. Han, J.G. Chen, L.X. Jiang, Z.M. Xu, and Q.S. Liu, First-principles molecular dynamics study of ionic structure and transport properties of LiF–NaF–AlF₃ molten salt, Chem. Phys. Lett., 706(2018), p. 237. doi: 10.1016/j.cplett.2018.06.005
[57]	H. Guo, J. Li, H.L. Zhang, et al., First-principles molecular dynamics investigation on KF–NaF–AlF₃ molten salt system, Chem. Phys. Lett., 730(2019), p. 587. doi: 10.1016/j.cplett.2019.06.060
[58]	C. Bessada, D. Zanghi, O. Pauvert, et al., High temperature EXAFS experiments in molten actinide fluorides: The challenge of a triple containment cell for radioactive and aggressive liquids, J. Nucl. Mater., 494(2017), p. 192. doi: 10.1016/j.jnucmat.2017.07.023
[59]	Y. Qiao, C.M. Pedersen, Y.X. Wang, and X.L. Hou, NMR insights on the properties of ZnCl₂ molten salt hydrate medium through its interaction with SnCl₄ and fructose, ACS Sustainable Chem. Eng., 2(2014), No. 11, p. 2576. doi: 10.1021/sc5004693
[60]	O. Pauvert, D. Zanghi, M. Salanne, et al., In situ experimental evidence for a nonmonotonous structural evolution with composition in the molten LiF–ZrF₄ system, J. Phys. Chem. B, 114(2010), No. 19, p. 6472. doi: 10.1021/jp912195j
[61]	C. Bessada and A.L. Rollet, In situ spectroscopy in molten fluoride salts, [in] F. Lantelme and H. Grou eds., Molten Salts Chemistry, Elsevier, 2013, p. 33.
[62]	O. Pauvert, M. Salanne, D. Zanghi, et al., Ion specific effects on the structure of molten AF–ZrF₄ systems (A⁺ = Li⁺, Na⁺, and K⁺), J. Phys. Chem. B, 115(2011), No. 29, p. 9160. doi: 10.1021/jp203137h
[63]	J.L. Hoard, Structures of complex Fluorides.1 Potassium heptafluocolumbate and potassium heptafluotantalate. The configuration of the heptafluocolumbate and heptafluotantalate ions, J. Am. Chem. Soc., 61(1939), No. 5, p. 1252. doi: 10.1021/ja01874a073
[64]	R.B. English, A.M. Heyns, and E.C. Reynhardt, An X-ray, NMR, infrared and Raman study of K₂TaF₇, J. Phys. C Solid State Phys., 16(1983), No. 5, p. 829. doi: 10.1088/0022-3719/16/5/010
[65]	C.C. Torardi, L.H. Brixner, and G. Blasse, Structure and luminescence of K₂TaF₇ and K₂NbF₇, J. Solid State Chem., 67(1987), No. 1, p. 21. doi: 10.1016/0022-4596(87)90333-1
[66]	X.D. Wang and S.Z. Duan, Identification of complex ions of Nb(V) in FLINAK–O²⁻ System by infrared spectra, Rare Met., 12(1993), No. 3, p. 209.
[67]	G.S. Chen, M. Okido, and T. Oki, Electrochemical studies of titanium ions (Ti⁴⁺) in equimolar KCl–NaCl molten salts with 1 wt% K₂TiF₆, Electrochim. Acta, 32(1987), No. 11, p. 1637. doi: 10.1016/0013-4686(87)90017-X
[68]	G.S. Chen, M. Okido, and T. Oki, Electrochemical studies of titanium in fluoride–chloride molten salts, J. Appl. Electrochem., 18(1988), No. 1, p. 80. doi: 10.1007/BF01016208
[69]	Y. Iwadate, T. Harada, T. Ohkubo, et al., Pulsed neutron diffraction study of NaNO₂ and KNO₂ pure melts, Electrochemistry, 77(2009), No. 8, p. 741. doi: 10.5796/electrochemistry.77.741
[70]	Y. Fang, C.H. Fang, L.J. Lin, and X.F. Qin, A study on the structure of calcium nitrate tetrahydrate molten salt, Salt Lake Res., 2007, No. 1, p. 39.
[71]	H.X. Zhou, F.Y. Zhu, W.C. Fang, Y.G. Zhou, H.Y. Liu, C.H. Fang, and Y. Fang, Effect of additives on phase transition temperature and undercooling temperature of CaCl₂·6H₂O–Ca(NO₃)₂·4H₂O and their molten salt structure, J. Mater. Sci. Eng., 37(2019), No. 1, p. 160.
[72]	I.S. Perelygin and G.P. Mikhailov, Manifestations of ion-ion interaction in the Raman spectra of the nitrate ion, J. Appl. Spectrosc., 48(1988), No. 5, p. 516. doi: 10.1007/BF00663465
[73]	R.W. Berg, D.H. Kerridge, and P.H. Larsen, NaNO₂ + NaNO₃ phase diagram: New data from DSC and Raman spectroscopy, J. Chem. Eng. Data, 51(2006), No. 1, p. 34. doi: 10.1021/je050105n
[74]	K.C. Xu and Y. Chen, Temperature-dependent Raman spectra of mixed crystals of NaNO₃–KNO₃: Evidence for limited solid solutions, J. Raman Spectrosc., 30(1999), No. 3, p. 173. doi: 10.1002/(SICI)1097-4555(199903)30:3<173::AID-JRS366>3.0.CO;2-2
[75]	S. Jayaraman, A.P. Thompson, O.A. von Lilienfeld, and E.J. Maginn, Molecular simulation of the thermal and transport properties of three alkali nitrate salts, Ind. Eng. Chem. Res., 49(2010), No. 2, p. 559. doi: 10.1021/ie9007216
[76]	N.A. Ponyatenko and I.V. Radchenko, Study of structure of binary fused monovalent nitratesd with Ca(NO₃)₂, Ba(NO₃)₂ and Sr(NO₃)₂ by the method of Raman scattering, Ukr. J. Phys., 14(1969), No. 1, p. 20.
[77]	N.A. Ponyatenko and I.V. Radchenko, Orientational interaction and rotational motion of the $ {\mathrm{N}\mathrm{O}}_{3}^{-} $ ion in monovalent nitrate melts, Opt. Spectrosc., 26(1969), p. 353.
[78]	B.L. Gao, F.G. Liu, and Z.W. Wang, Raman spectra of NaNO₂–KNO₃–NaNO₃ ternary molten salts, Rare Met., 28(2009), No. S1, p. 581.
[79]	J.Y. Zhao, Structure Study on the Ternary NaNO₃–KNO₃–NaNO₂ Molten Sallts [Dissertation], Qinghai Normal University, Xining, 2020, p. 77.
[80]	H.Y. Hou, J.L. You, Y.Q. Wu, H. Chen, and G.C. Jiang, Raman spectroscopic study of alkali carbonates, Chin. J. Light. Scatt., 13(2001), No. 3, p. 162.
[81]	L.J. Chen, J. Zuo, and C.J. Lin, In-situ Raman spectroscopy studies on the electrode process of cathode in MCFC, [in] Proceedings of the 13th Chinese Symposium on Molecular Spectroscopy, Xiamen, 2004, p. 199.
[82]	H. Ohata, K. Takeuchi, K. Ui, and N. Koura, The structure of molten lithium carbonate calculated by DFT and MD simulations, ECS Trans., 6(2007), No. 14, p. 57. doi: 10.1149/1.2811943
[83]	N. Koura, S. Kohara, K. Takeuchi, et al., Alkali carbonates: Raman spectroscopy, ab initio calculations, and structure, J. Mol. Struct., 382(1996), No. 3, p. 163. doi: 10.1016/0022-2860(96)09314-3
[84]	Y.Z. Wang, Influence of Additives on the Structure and Properties of Aluminum Electrolysis Molten Salt system [Dissertation], Kunming University of Science and Technology, Kunming, 2015, p. 93.
[85]	S.L. Jiang, C.M. Ye, Y.L. Liu, et al., Insights into the effects of fluoride anions on the electrochemical behavior and solution structure of trivalent samarium in LiCl–KCl molten salt, Electrochim. Acta, 439(2023), art. No. 141733. doi: 10.1016/j.electacta.2022.141733
[86]	J.L. You, T. Zhao, S. Petrik, Y.Y. Wang, and X.W. Liu, In-situ high temperature Raman spectroscopy and quantum chemical Ab initio simulation on species in molten NaF–AlF₃ fluorides, [in] Proceedings of the 17th National Symposium on Molecular Spectroscopy, Shaoguan, 2012, p. 223.
[87]	J. Wang and C.L. Liu, Temperature and composition dependences of shear viscosities for molten alkali metal chloride binary systems by molecular dynamics simulation, J. Mol. Liq., 273(2019), p. 447. doi: 10.1016/j.molliq.2018.10.062
[88]	Y.L. Liu, J.H. Lan, L. Wang, et al., The influence of F⁻ ion on the electrochemical behavior and coordination properties of uranium in LiCl–KCl molten salt, Electrochimica Acta, 404(2022), art. No. 139573. doi: 10.1016/j.electacta.2021.139573
[89]	Y.K. Wu, G.Q. Yan, S. Chen, and L.J. Wang, Electrochemistry of Hf(IV) in NaCl–KCl–NaF–K₂HfF₆ molten salts, Int. J. Miner. Metall. Mater., 27(2020), No. 12, p. 1644. doi: 10.1007/s12613-020-2083-3
[90]	J.X. Song, Q.Y. Wang, J.Y. Wu, S.Q. Jiao, and H.M. Zhu, The influence of fluoride ions on the equilibrium between titanium ions and titanium metal in fused alkali chloride melts, Faraday Discuss., 190(2016), p. 421. doi: 10.1039/C6FD00007J
[91]	S.S. Liu, S.L. Li, C.H. Liu, J.L. He, and J.X. Song, Effect of fluoride ions on coordination structure of titanium in molten NaCl–KCl, Int. J. Miner. Metall. Mater., 30(2023), No. 5, p. 868. doi: 10.1007/s12613-022-2527-z
[92]	R. Yuan, C. Lü, H.L. Wan, et al., Effect of fluoride addition on electrochemical behaviors of V(III) in molten LiCl−KCl, Trans. Monferrous Met. Soc. China, 32(2022), No. 8, p. 2736. doi: 10.1016/S1003-6326(22)65980-6
[93]	X. Bai, S. Li, J. He, and J. Song, Effect of fluoride-ion on the electrochemical behavior of tantalum ion in NaCl–KCl molten salt, J. Electrochem. Soc., 169(2022), No. 8, art. No. 082504. doi: 10.1149/1945-7111/ac8379
[94]	H. Guo, J. Li, H.L. Zhang, et al., Study on micro-structure and transport properties of KF–NaF–AlF₃–Al₂O₃ system by first-principles molecular dynamics simulation, J. Fluorine Chem., 235(2020), art. No. 109546. doi: 10.1016/j.jfluchem.2020.109546
[95]	C.Y. Wang, Raman Spectroscopy and Theoretical Calculation of Metal Fluoride and Fluoride Oxides in Fluoride Molten Salt [Dissertation], University of Chinese Academy of Sciences, Beijing, 2021, p. 135.
[96]	X. Chen, H. Fu, and C. Wang, Influence of oxide ions on the speciation in molten KF–ZrF₄ and KF–HfF₄: A Raman spectroscopic and theoretical investigation, J. Mol. Liq., 342(2021), art. No. 117476. doi: 10.1016/j.molliq.2021.117476
[97]	X. Wang, C.F. Liao, and L.S. Luo, Effect of Nd₂O₃ on the properties and structure of AlF₃–(Na/Li)F–Al₂O₃ melt, Chin. Rare Earth, 38(2017), No. 5, p. 1.
[98]	X.Y. Liu, Y.J. Li, B.Z. Wang, and C.Y. Wang, Raman and density functional theory studies of lutecium fluoride and oxyfluoride structures in molten FLiNaK, Spectrochim. Acta A: Mol. Biomol. Spectrosc., 251(2021), art. No. 119435. doi: 10.1016/j.saa.2021.119435