Thorium Thorium is a chemical element; it has symbol Th and atomic number 90. Thorium is a weakly radioactive light silver metal which tarnishes olive grey when it is exposed to air, forming thorium dioxide; it is moderately soft, malleable, and ha ...

(IV)

fluoride Fluoride (). According to this source, is a possible pronunciation in British English. is an Inorganic chemistry, inorganic, Monatomic ion, monatomic Ion#Anions and cations, anion of fluorine, with the chemical formula (also written ), whose ...

( Th F₄) is an

inorganic An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds⁠that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemistry''. Inor ...

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

. It is a white

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption (chemistry), absorption or adsorption from the surrounding Natural environment, environment, which is usually at normal or room temperature. If water mol ...

powder which can be produced by reacting thorium with

fluorine Fluorine is a chemical element; it has Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standard temperature and pressure, standard conditions as pale yellow Diatomic molecule, diatomic gas. Fluorine is extre ...

gas. At temperatures above 500 °C, it reacts with atmospheric moisture to produce ThOF₂.

Uses

Despite its (mild) radioactivity, thorium fluoride is used as an antireflection material in multilayered optical coatings. It has excellent optical transparency in the range 0.35–12 μm, and its radiation is primarily due to

alpha particle Alpha particles, also called alpha rays or alpha radiation, consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay but may also be produce ...

s, which can be easily stopped by a thin cover layer of another material. However, like all alpha emitters, thorium is potentially hazardous if incorporated, which means safety should focus on reducing or eliminating this danger. In addition to its radioactivity, thorium is also a chemically

toxic heavy metal A toxic heavy metal is a common but misleading term for a metal-like element noted for its potential toxicity. Not all heavy metals are toxic and some toxic metals are not heavy. Elements often discussed as toxic include cadmium, mercury and ...

. Thorium fluoride was used in making

carbon arc lamp An arc lamp or arc light is a lamp that produces light by an electric arc (also called a voltaic arc). The carbon arc light, which consists of an arc between carbon electrodes in air, invented by Humphry Davy in the first decade of the 1800s, ...

s, which provided high-intensity illumination for movie projectors and search lights.Thorium tetrafluoride
International Bio-Analytical Industries, Inc.

References

{{Actinide halides Fluorides Actinide halides Thorium(IV) compounds

Uses

See also

References