Thorium (IV) fluoride

Crystal structure
__ Th 4+      __ F -
Crystal system	monoclinic
Space group	I 2 / c (No. 15, position 6)
Lattice parameters	a = 1313 pm b = 1102 pm c = 862 pm β = 126 °
General
Surname	Thorium (IV) fluoride
other names	Thorium tetrafluoride
Ratio formula	ThF 4
Brief description	white solid
External identifiers / databases
CAS number 13709-59-6 EC number 237-259-6 ECHA InfoCard 100,033,857 PubChem 83680 Wikidata Q2522890
properties
Molar mass	308.03 g mol −1
Physical state	firmly
density	6.32 g cm −3
Melting point	1068 ° C
boiling point	1680 ° C
Refractive index	1.52
Hazard and safety information
Radioactive
GHS hazard labeling no classification available
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Thorium (IV) fluoride is an inorganic chemical compound of thorium from the group of fluorides .

Extraction and presentation

Thorium (IV) fluoride can be obtained by reacting hydrogen fluoride with thorium (IV) oxide at 550 ° C or thorium (IV) hydride at 350 ° C.

${\displaystyle \mathrm {ThO_{2}+4\ HF\longrightarrow ThF_{4}+2\ H_{2}O} }$

${\displaystyle \mathrm {2\ Th_{4}H_{15}+32\ HF\longrightarrow 8\ ThF_{4}+31\ H_{2}} }$

It is also possible to display it by reacting thorium (IV) oxide with ammonium hydrogen difluoride at 500 ° C.

${\displaystyle \mathrm {ThO_{2}+4\ NH_{4}HF_{2}\longrightarrow ThF_{4}+4\ NH_{4}F+2\ H_{2}O} }$

Thorium fluoride can also be obtained from thorium and fluorine .

properties

Thorium (IV) fluoride is a white solid that is in the form of a cryptocrystalline powder or single-refracting, iridescent crystals. It is insoluble in water and has a monoclinic crystal structure with the space group I 2 / c (space group number 15, position 6) isotype with zirconium (IV) fluoride (a = 1313 pm, b = 1102 pm, c = 862 pm , β = 126 °). In the crystal structure there are square antiprisms ThF ₈ . The compound reacts with atmospheric moisture at temperatures above 500 ° C to form thorium oxide fluoride . When represented from solutions, it is in the form of hydrates (octa-, tetra-, dihydrate, etc.) of which the hemihydrate is the only one whose structure is known. The water of crystallization can be removed from the hemihydrate by heating it to 400 ° C in a vacuum.

use

Thorium (IV) fluoride is used in the manufacture of pure thorium and high temperature ceramics. It also serves as a sputtering target for the production of thin films with a low refractive index without absorption in the visible and UV range. It is also used in the manufacture of carbon arc lamps .

In addition, it is planned to use thorium (IV) fluoride as fuel for a certain type of breeder reactor ( liquid fluoride thorium reactor , LFTR). The first examples of these reactors have been under development in Japan since 2010 and in China since 2014.

Individual evidence

1. ↑ ^{a b c d e f g} Georg Brauer (Ed.), With the collaboration of Marianne Baudler u. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume I, Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6 , p. 1135.
2. ↑ William M. Haynes (Ed.): CRC Handbook of Chemistry and Physics . 93rd edition. CRC Press, 2012, p. 95 ( limited preview in Google Book search).
3. ^ Ronald R. Willey: Practical Design and Production of Optical Thin Films . CRC Press, 2002, pp. 276 ( limited preview in Google Book search).
4. ↑ The hazards emanating from radioactivity do not belong to the properties to be classified according to the GHS labeling. With regard to other hazards, this substance has either not yet been classified or a reliable and citable source has not yet been found.
5. ↑ ^{a b c} Dale L. Perry: Handbook of Inorganic Compounds . 2nd Edition. CRC Press, 2011, ISBN 978-1-4398-1462-8 , pp. 426 ( limited preview in Google Book search).
6. ↑ Lester R. Morss, Norman M. Edelstein, J. Fuger (Eds.): The Chemistry of the Actinide and Transactinide Elements (Set Vol.1-6) . Springer, 2010, ISBN 978-94-007-0211-0 , pp. 79 ( limited preview in Google Book search).
7. ↑ Advances in Inorganic Chemistry and Radiochemistry . Vol. 2. Academic Press, 1960, ISBN 0-08-057851-9 , pp. 208 ( limited preview in Google Book search).
8. ↑ John J. McKetta Jr (Ed.): Thermoplastics to Trays (=  Encyclopedia of Chemical Processing and Design . Volume 58). CRC Press, 1996, ISBN 0-8247-2609-X , pp. 81 ( limited preview in Google Book search).
9. ↑ Michael Odenwald: Guarantor for world energy supply . Focus online, May 5, 2011, page 3, accessed May 29, 2014.