Cadmium fluoride (CdF2) is a mostly water-insoluble source of cadmium used in oxygen-sensitive applications, such as the production of metallic alloys. It is an inorganic compound that consists of cadmium and fluorine. It’s a white, crystalline solid and is used in various applications, including optics, ceramics, and as a source of fluoride ions in chemical reactions.
In extremely low concentrations (ppm), this and other fluoride compounds are used in limited medical treatment protocols. Fluoride compounds also have significant uses in synthetic organic chemistry. The standard enthalpy has been found to be -167.39 kcal. mole−1 and the Gibbs energy of formation has been found to be -155.4 kcal. mole−1, and the heat of sublimation was determined to be 76 kcal. mole−1.
Preparation
Cadmium fluoride is prepared by the reaction of gaseous fluorine or hydrogen fluoride with cadmium metal or its salts, such as the chloride, oxide, or sulfate. It may also be obtained by dissolving cadmium carbonate in 40% hydrofluoric acid solution, evaporating the solution and drying in a vacuum at 150 °C.
Another method of preparing it is to mix cadmium chloride and ammonium fluoride solutions, followed by crystallization. The insoluble cadmium fluoride is filtered from solution. Due to the toxicity of cadmium and its compounds, handling CdF₂ requires appropriate safety measures, including personal protective equipment and proper disposal methods.
Properties
- Chemical formula: CdF2
- Molar mass: 150.41 g/mol
- Appearance: grey or white-grey crystals
- Density: 6.33 g/cm3, solid
- Melting point: 1,110 °C (2,030 °F; 1,380 K)
- Boiling point: 1,748 °C (3,178 °F; 2,021 K)
- Solubility in water: 4.35 g/100 mL
Uses
- Optical Applications: Due to its optical properties, CdF₂ is used in the manufacture of lenses and windows for UV and infrared applications.
- Ceramics: It can be used in the production of certain types of ceramics.
- Fluoride Source: CdF₂ can act as a fluoride source in various chemical processes.
Natural Occurrence
Cadmium fluoride is not commonly found in nature in its pure form. However, cadmium can be found in minerals such as greenockite (CdS), and fluoride ions can be present in various minerals.
Safety
Cadmium compounds are toxic and can pose health risks. Exposure can lead to serious health issues, including lung and kidney damage, so handling CdF₂ requires appropriate safety measures.
