Description
Ammonium bifluoride purified is a highly water-soluble, white crystalline inorganic salt with the formula NH₄HF₂, used widely in industrial applications for its etching, cleaning, and metal treatment properties.
Chemical and Physical Properties
Formula: NH₄HF₂ (ammonium hydrogen difluoride).
Molar mass: 57.04 g/mol.
Appearance: White crystalline solid, often hygroscopic (absorbs moisture from air).
Melting point: 124.6 °C; boils/decomposes ~240 °C.
Density: 1.5 g/cm³.
Solubility in water: Very high (60–156 g/100 mL, depending on temperature).
pH (5% solution): around 3.5 (acidic).
Purity (purified/extra pure): typically ≥98%.
Major Uses and Applications
Glass etching and frosting: Ammonium bifluoride is a powerful etchant for glass and silicates, used in glass, lamp, and optical industries.
Metal treatment and cleaning: Removes oxides, scales, and stains from metal surfaces, and is a cleaning agent for steel, aluminum, and equipment.
Surface polishing: Plays a role in precision cleaning of ceramics and metal parts.
Chemical intermediate: Used in the production of hydrofluoric acid and as a source of fluoride ions for industrial synthesis.
Textiles and dyes: Acts as a mordant and dyeing auxiliary.
Safety and Handling
Highly corrosive and toxic; causes severe skin burns and eye damage.
Releases corrosive hydrogen fluoride vapors when moist or heated—must be handled only with proper protective equipment in well-ventilated conditions.
Hygroscopic: Store in airtight containers, away from acids and moisture.
Non-flammable, but reacts with metals and glass.
Ammonium bifluoride purified is valued for its versatility in industrial etching, cleaning, and processing, but demands careful handling due to its corrosivity and toxicity