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Properties of Ammonium Bifluoride
Ammonium bifluoride has the formula NH4(HF2), or written another way, NH4F*HF.
Ammonium bifluoride is a colorless crystalline substance that is highly soluble in water. Its crystal lattice is hexagonal. In the crystal, the NH4+ cation is surrounded by four HF2- anions, which form a tetrahedron.
Decomposition temperature: when heated above 238 degrees Celsius, the substance decomposes into gaseous substances according to the following formula:
NH4(HF2) = NH3↑ + 2HF↑
HF is hydrofluoric acid.
In various chemical reactions, Ammonium bifluoride can act as a reducing agent — when reacting with acids according to the following reaction:
NH4(HF2) + H2SO4 = NH4SO4 + 2HF↑
And with alkalis according to the formula:
NH4(HF2) + 2NaOH = 2NaF + NH3↑ + 2 H2O
The melting point of NH4(HF2) is 126.45 degrees Celsius.
Addition processes of NH4F are possible through the gas phase, in aqueous solution, and when mixing solid substances.
Molten Ammonium bifluoride is a fairly active fluorinating agent, compared to gaseous HF (hydrofluoric acid). For example, when using hydrofluoric acid, processes generally stop at the formation of oxyfluorides, for example when fluorinating Titanium, Tantalum, and others. When using ammonium bifluoride, this stage can be skipped and the process can proceed directly to the formation of fluorometallates; this property is used to obtain fluorine compounds of rare earth metals, platinoid compounds, and others.
During fluorination, double compounds are usually formed. An example is the fluorination reaction of aluminum oxide:
Al2O3 + 6NH4HF2 = 2(NH4)3AlF6 + 2H2O — this is the first stage of the process, which proceeds at a temperature of 130 degrees Celsius.
The next stage is at 305 degrees: (NH4)3AlF6 = (NH4)AlF4 + 2NH3 + 2HF
And the final stage occurs at 400 degrees: (NH4)AlF4 = AlF3 + NH3 + HF
Applications of Ammonium Bifluoride
One of the applications of ammonium bifluoride in industry is for cleaning deposits of iron oxides and/or in the presence of various silicon compounds, solutions containing Ammonium bifluoride are used.
The reaction with Silicon oxide looks like this:
SiO2 + 3.5NH4F*HF = (NH4)3SiF7 + 2H2O + 0.5NH3 — for temperatures of 200 degrees Celsius and above.
(NH4)3SiF7 = (NH4)2SiF6 + NH3 + HF — this reaction proceeds in the temperature range of 170-190 degrees.
This ability to bind silicon compounds is used in oil production — for acid treatment of injection wells in clay-bearing formations. Ammonium bifluoride is used on par with hydrofluoric acid.
Its reaction with iron oxides is used for cleaning pipes and boilers in various systems.
Fluorination processes are used in metallurgy for obtaining fluorine compounds, for example, Sodium fluoride.
You can buy Ammonium bifluoride wholesale from our company by writing to order@chimko.com or calling us at +7(495)133-02-40
