Preparation of Manganese Fluoride MnF2
The mixture of MnF2 and MnF3 can be obtained by the direct action of manganese, manganese carbide or manganese chloride and fluorine. And manganese iodide (Ⅱ) and fluorine can get pure Manganese Fluoride MnF2. When MnF3 is heated, it loses part of its fluorine and generates low-valent fluorides.
Permanganese fluoride MnF3 is preferably formed by fluorination of manganese(III) iodide. It is a solid, although its decomposition pressure is lower than 10.1325kPa (0.1 atmospheric pressure) at 600°C, it still releases fluorine when heated. It is a strong fluorinating agent that reacts with sulfur, boron, silicon, carbon, phosphorus trichloride and carbon tetrachloride when heated. It is used to fluorinate gaseous hydrocarbons.
Dissolve Mn2O3 in hydrofluoric acid and concentrate the solution to crystallize, or reduce potassium permanganate with low manganese salt in hydrofluoric acid to obtain hydrated Manganese Fluoride MnF2MnF3·3H2O. This compound is soluble in cold water without decomposition, and is also stable in hot water in the presence of hydrofluoric acid. Anhydrous tri-Manganese Fluoride MnF2 slowly decomposes into di-Manganese Fluoride MnF2, hydrated manganese dioxide and hydrogen fluoride in water.