Abstract: Aiming to address the unclear reaction mechanisms of trace impurities in electron-grade hydrofluoric acid, this study focuses on fluoromanganate-like metal complexes. It systematically investigates the reaction pathways of trace impurity manganese (Mn) and other metal impurity ions (sodium [Na+], calcium [Ca2+], and aluminum [Al3+], representing typical mono-, di-, and tri-valent impurity ions) within the hydrofluoric acid system. This is achieved through density functional theory (DFT) calculations, combined with analyses of electrostatic charge distributions, differential charge density, and binding energy calculations to reveal the stability of the reaction products (AlMnF8, CaMnF6, NaMnF6) and their potential for separation from hydrofluoric acid (HF). The results show that AlMnF8, generated by the reaction of Al3+ with Mn, has the lowest total system energy (-1.135 Ha) and the most stable structure; the binding energy analysis further confirms that the absolute value of the binding energy of AlMnF8 with HF (0.018 Ha) is lower than that of NaMnF6 (0.028 Ha) and CaMnF6 (0.029 Ha), which suggests that it can be more easily detached from HF solution by physical separation. indicating that it is easier to be removed by physical separation in HF solution. This study provides a theoretical basis for the efficient removal of trace manganese complexes in electronic grade HF.

Key words: Electronic grade hydrofluoric acid, Density functional theory calculations, Fluoromanganate, Trace impurity removal