Thorium(IV) fluoride
Thorium(IV) fluoride Thorium tetrafluoride
3D model (JSmol)
ECHA InfoCard 100.033.857 Edit this at Wikidata
EC Number
  • 237-259-6
  • InChI=1S/4FH.Th/h4*1H;/q;;;;+4/p-4
  • F[Th](F)(F)F
Molar mass 308.03 g/mol
Appearance white crystals
Density 6.3 g/cm3
Melting point 1,110 °C (2,030 °F; 1,380 K)
Boiling point 1,680 °C (3,060 °F; 1,950 K)
Monoclinic, mS60
C12/c1, No. 15
Flash point Non-flammable
Related compounds
Other anions
Thorium(IV) chloride
Thorium(IV) bromide
Thorium(IV) iodide
Other cations
Protactinium(IV) fluoride
Uranium(IV) fluoride
Neptunium(IV) fluoride
Plutonium(IV) fluoride
Related compounds
Thorium dioxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Thorium(IV) fluoride (ThF4) is an inorganic chemical compound. It is a white hygroscopic powder which can be produced by reacting thorium with fluorine gas. At temperatures above 500 °C, it reacts with atmospheric moisture to produce ThOF2.[1]


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 particles, which can be easily stopped by a thin cover layer of another material.[2][3] 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.

Thorium fluoride was used[when?] in making carbon arc lamps, which provided high-intensity illumination for movie projectors and search lights.[4][5]

See also


  1. ^ Dale L. Perry, Sidney L. Phillips (1995). Handbook of inorganic compounds. CRC Press. p. 412. ISBN 0-8493-8671-3.
  2. ^ James D. Rancourt (1996). Optical thin films: user handbook. SPIE Press. p. 196. ISBN 0-8194-2285-1.
  3. ^ W. Heitmann and E. Ritter (1968). "Production and properties of vacuum evaporated films of thorium fluoride". Appl. Opt. 7 (2): 307–9. Bibcode:1968ApOpt...7..307H. doi:10.1364/AO.7.000307. PMID 20062461.
  4. ^ McKetta, John J. (1996). Encyclopedia of Chemical Processing and Design: Thermoplastics to Trays, Separation, Useful Capacity. CRC Press. p. 81. ISBN 0-8247-2609-X.
  5. ^ Thorium tetrafluoride Archived 2013-02-16 at International Bio-Analytical Industries, Inc.