Barium fluoride is an inorganic chemical compound with the molecular formula BaF2. It is a solid that occurs in nature as the rare mineral frankdicksonite and has no color. Moreover, it adopts the fluorite structure and at the high pressure, it adopts the PbCl2structure. Like CaF2, it is insoluble when putting inside the water. Above ca. 500 °C, the BaF2is corroded due to the moisture, but in the case of dry environments, it can come in use for up to 800 °C. The Barium Fluoride Formula is given below for a better understanding.
The prolonged exposure to moisture degrades the transmission in the vacuum UV range. However, it is less resistant to water as compared to the calcium fluoride, but it is the most resistant one in all the optical fluorides to high energy radiation, though its far-ultraviolet transmittance is lesser than theirs. It is so hard, very sensitive to the thermal shock and fractures very easily.
Formula and Structure
The molecular formula for the chemical compound barium fluoride is BaF2. It has a chemical structure that is available below in the form of an image that is in the common representations that we generally use for the organic molecules.
                      Source:Pubchem
Optical Properties
The barium fluoride is transparent from the ultraviolet to the infrared, ranging from 150 – 200 nm to 11 – 11.5 µm. Moreover, we also use it in the windows for infrared spectroscopy, particularly in the field of analysis of the fuel oil. Its transmittance at 200 nm is relatively less (0.60), but at 500 nm it goes higher up to 0.96 – 0.97 and consistently stays at the same level until 9 µm, then it starts to fall off (0.85 for 10 µm and 0.42 for 12 µm). Moreover, the refractive index is about 1.46 from 700 nm to 5 µm.
Chemical Properties
The melting point of the barium fluoride is 1,368 °C, whereas, it has a boiling point of 2,260 °C. It carries a density of 4.89 g/cm³. Moreover, the molar mass of the barium fluoride is 175.34 g/mol. It is slightly soluble in the water (H2O).
Gas-Phase Structure
In the vapor phase, the BaF2molecule is non-linear with an F-Ba-F angle of about 108°. Its nonlinearity is an exception to the theory of VSEPR. The initial calculations give an indication that the contributions from (D) orbitals in the shell below the valence shell are the cause. Another proposal is that the polarization of the electron core of the barium atom makes an approximately tetrahedral distribution of the charge which interacts with the bonds of Ba-F.
Uses
The barium fluoride is useful for making the optical components, for example, lens, etc. Moreover, the industrialists use it in the process of manufacturing the carbon brushes for the DC motors. These also come in use for the manufacturing of the glass.
Solved Example for You
Question: The solubility of the chemical compound barium fluoride i.e. BaF2, is 3.15 x 10-3 M at 25 °C. Calculate the solubility product and Ksp.
Answer:
The dissociation reaction of compound BaF2in water is:
BaF2(s) ↔ Ba+ (aq) + 2 F- (aq)
This reaction shows that for every single mole of BaF2that dissolves, 1 mole of Ba+ and 2 moles of F- are formed as a result. The solubility is similar to the concentration of the Ba ions in the solution.
Solubility = [Ba+] = 7.94 x 10-3M
[F–] = 2 [Ba+]
Ksp = [Ba+][F–]2
Ksp = ([Ba+])(2 [Ba+])2
Ksp = 4[Ba+]3
Ksp = 4(7.94 x 10-3M)3
Ksp = 4(5 x 10-7)
Ksp = 2 x 10-6
The solubility product of barium fluoride (BaF2) is 2 x 10-6.
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