What Is Barium Fluoride?
Barium fluoride is an ionic compound consisting of barium and fluoride ions, represented by the formula BaF2.
Its CAS registration number is 7787-32-8. It appears as a white powder at room temperature and pressure. Fluoride crystals are known for their ability to transmit infrared rays, with barium fluoride standing out for its wide range of transmitted wavelengths.
Due to this, it is used in manufacturing lenses and infrared glass. Barium fluoride is classified as a hazardous chemical and as a deleterious substance.
Uses of Barium Fluoride
Barium fluoride is utilized in high-purity aluminum smelting, as a flux for welding rods, and in glazes. It transmits a broad spectrum of electromagnetic waves, from ultraviolet to infrared (wavelengths from about 0.15 to 14 μm).
Its applications include lenses and prisms for a wide range of wavelengths, window plates in infrared spectroscopy, and scintillators in X-ray detection. It is also used in optics for digital SLR cameras, as a base material for optical fibers, cell windows for NDIR gas measurement, observation windows for temperature measurement in radiation thermometers and infrared cameras, and protective windows for mid-infrared camera lenses.
Among fluoride crystals, barium fluoride transmits the widest range of wavelengths and is more resistant to high-energy electromagnetic waves than calcium fluoride and other fluorides.
Properties of Barium Fluoride
Barium fluoride, with a molecular weight of 175.324, melts at 1,253 °C and boils at 2,260 °C. It is an odorless white solid at room temperature. With a density of 4.893 g/mL and a solubility in water of 1.58 g/L at 10 °C, it is almost insoluble in water.
It remains stable under normal handling conditions but is sensitive to sudden heating and shock. Storage in a cool, dark place away from direct sunlight is recommended.
It reacts with oxidizing and reducing agents. Although nonflammable, it can decompose into highly toxic hydrogen fluoride gas in a fire.
Types of Barium Fluoride
Barium fluoride is available mainly as reagent-grade products for research and development and as raw materials for industrial use. For R&D purposes, it comes in convenient sizes like 20g, 50g, 100g, and 500g. These products are typically stable at room temperature.
For industrial applications, particularly in glass and lens manufacturing, it is supplied in larger quantities, such as 20 kg bags, for easy handling in factories.
Other Information on Barium Fluoride
1. Barium Fluoride in Nature
Barium fluoride occurs naturally as frankdixonite, found in the Carlin gold deposit in Eureka County, Nevada, alongside quartz.
2. Crystal Structure of Barium Fluoride
At room temperature and pressure, barium fluoride has a structure similar to CaF2, but under high pressure, it adopts a structure akin to PbCl2.
3. Safety and Hazard Information of Barium Fluoride
Barium fluoride is recognized for several hazards:
- Toxic if swallowed
- Causes serious eye irritation
- May cause respiratory irritation
- Potential risk of harm to the cardiovascular, nervous, muscular systems, kidneys, and bones from long-term or repeated exposure
Given these hazards, it is regulated under various laws and classified as a deleterious substance and as a hazardous chemical. It is also classified under environmental protection laws, emphasizing the need for careful disposal. Despite being nonflammable, it is regulated under fire service laws due to the potential generation of hydrogen fluoride gas during combustion.