Description
Lanthanum trifluorides (chemical formula: LaF3) is a kind of high-melting, ionic compound of lanthanum and fluorine. It is a component of the multimetal fluoride glass such as ZBLAN. It is majorly used as a solid membrane electrode for manufacturing the into fluoride sensitive (F-1) Ion-selective probes. It also has applications in fiber optics, fluorescent lamps and radiation applications. Lanthanum fluoride can also be doped with Nd3+ and has special applications as a scintillating material.
Uses
Lanthanum fluoride is used in phosphor lamp coating. Mixed with other rare earths, it is used in carbon arc electrodes and lasers. Also, the fluoride is used in the production of lanthanum metal, an intermediate step in the manufacture of high purity metal.
Lanthanum fluoride, is mainly applied in specialty glass, water treatment and catalyst, and also as the main raw materials for making Lanthanum Metal. Lanthanum Fluoride (LaF3) is an essential component of a heavy Fluoride glass named ZBLAN. This glass has superior transmittance in the infrared range and is therefore used for fiber-optical communication systems. Mixed with Europium Fluoride, it is also applied in the crystal membrane of Fluoride ion-selective electrodes.
Preparation
Lanthanum fluoride may be precipitated by adding hydrofluoric acid to an aqueous solution of lanthanum nitrate or chloride:
La(NO3)3 + 3HF → LaF3 + 3HNO3
The compound also can be made by heating lanthanum oxide with ammonium fluoride in hydrofluoric acid at 300 to 400°C. Ammonium fluoride released in the reaction sublimes at this temperature:
La2O3 + 6NH4F•6HF → 2LaF3 + 6NH4F↑ + 3H2O↑
Anhydrous lanthanum fluoride also may be made by passing dry hydrogen fluoride over lanthanum oxide. This process, however, produces trace amounts of lanthanum oxyfluoride, LaOF. Highly purified material may be obtained by passing dry purified HF over molten fluoride in a platinum crucible.
References
http://172.16.24.179/www.crystran.co.uk/userfiles/files/lanthanum-fluoride-laf3-ion-selective-electrodes.pdf
https://en.wikipedia.org/wiki/Lanthanum_trifluoride
http://www.azom.com/article.aspx?ArticleID=2348
Chemical Properties
off-white powder
Physical properties
White hexagonal crystal; hygroscopic; density 5.9 g/cm
3; melts at 1,493°C; insoluble in water and acids.
Uses
Lanthanum fluoride is a white powder used to coat the inside of
phosphorus lamps and lasers.
Uses
Lanthanum fluoride, anhydrous is employed extensively in the preparation and study of fluoride glasses.
Flammability and Explosibility
Non flammable
Structure and conformation
The space lattice of LaF3 belongs to the tysonite structure.
