Zinc fluoride is an inorganic chemical compound with the chemical formula ZnF2. It appears as a white crystalline solid. It is encountered as the anhydrous form and also as the tetrahydrate, ZnF2·4H2O (rhombohedral crystal structure). It has a high melting point and has the rutile structure containing 6 coordinate zinc, which suggests appreciable ionic character in its chemical bonding. Unlike the other zinc halides, ZnCl2, ZnBr2 and ZnI2, it is not very soluble in water.
Due to its low refractive index and transparency in the UV and visible ranges, it is used in lenses and windows for optical instruments. It’s used in the production of semiconductor materials. It can be utilized as a source of fluoride ions in chemical reactions and industrial processes.
Properties
It is relatively stable and does not readily react with water. It reacts with strong acids to form zinc salts and hydrogen fluoride (HF). It typically crystallizes in a hexagonal or cubic structure. It has good optical transparency in the ultraviolet and visible regions, making it useful in optical applications.
- Chemical formula: ZnF2
- Molar mass: 103.406 g/mol (anhydrous), 175.45 g/mol (tetrahydrate)
- Appearance: white needles, hygroscopic
- Density: 4.95 g/cm3 (anhydrous), 2.30 g/cm3 (tetrahydrate)
- Melting point: 872 °C (1,602 °F; 1,145 K) (anhydrous), 100 °C, decomposes (tetrahydrate)
- Boiling point: 1,500 °C (2,730 °F; 1,770 K) (anhydrous)
- Solubility in water: .000052 g/(100 mL) (anhydrous), 1.52 g/(100 mL), 20 °C (tetrahydrate)
- Solubility: sparingly soluble in HCl, HNO3, ammonia
Natural Occurrence
Zinc fluoride can occur naturally in some mineral deposits, although it is not commonly found in nature compared to other zinc compounds.
Synthetic Production
It is primarily produced synthetically for various industrial applications.
Applications
- Used in optics for lenses and windows due to its optical properties.
- Employed in the manufacture of ceramic materials and in the production of fluorine-containing compounds.
- Sometimes used in dental applications as a fluoride source.
