Arsenic (III) fluoride

Structural formula
General
Surname	Arsenic (III) fluoride
other names	Arsenic trifluoride
Molecular formula	AsF 3
Brief description	colorless liquid that smokes in air
External identifiers / databases
CAS number 7784-35-2 EC number 232-060-0 ECHA InfoCard 100.029.145 PubChem 24571 Wikidata Q425213
properties
Molar mass	131.91 g mol −1
Physical state	liquid
density	2.7 g cm −3
Melting point	−5.95 ° C
boiling point	57.1 ° C at 1.0 bar
solubility	Decomposes in water soluble in diethyl ether , ethanol and benzene
Dipole moment	2.59 (5) D (8.6 x 10 -30  C  ·  m )
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 331-301-410 P: ?
Thermodynamic properties
ΔH f 0	−821.3 kJ / mol
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Arsenic trifluoride is a chemical compound consisting of the elements arsenic and fluorine .

Extraction

Arsenic trifluoride can be produced by reacting anhydrous hydrogen fluoride with arsenic (III) oxide at 140 ° C.

${\displaystyle \mathrm {As_{2}O_{3}+6\ HF\longrightarrow 2\ AsF_{3}+3\ H_{2}O} }$

It can also be obtained by reacting arsenic trioxide with fluorosulfonic acid .

${\displaystyle \mathrm {2\ As_{2}O_{3}+6\ HSO_{3}F\longrightarrow 2\ AsF_{3}+SO_{3}+3\ H_{2}SO_{4}+As_{2}O(SO_{4})_{2}} }$

In the laboratory, the compound is easily available by preparing a mixture of arsenic (III) oxide and calcium fluoride with concentrated sulfuric acid and then distilling it:

${\displaystyle {\ce {As2O3 + 3 CaF2 + 3 H2SO4 -> 2 AsF3 + 3 CaSO4 + 3 H2O}}}$

properties

Arsenic trifluoride is a colorless liquid that smokes in the air and attacks glass. Their enthalpy of formation is −305.0 kJ / mol. It is a weaker Lewis base than phosphorus trifluoride (PF ₃ ), but a stronger Lewis acid than this. The ions AsF ₂ ⁺ and AsF ₄ ^{- are} derived from arsenic trifluoride and are also formed in equal parts in the pure substance through autoionization .

use

Arsenic trifluoride is used for ion implantation and for the production of arsenic (V) fluoride .

safety instructions

Arsenic trifluoride is classified as carcinogenic and very toxic.

Individual evidence

1. ↑ ^{a b c} Entry on arsenic fluoride. In: Römpp Online . Georg Thieme Verlag, accessed on July 14, 2014.
2. ↑ Arsenic (III) fluoride at webelements.com
3. ↑ ^{a b c} C. J. Hoffman: Arsenic (III) fluoride . In: JC Bailar, Jr. (Ed.): Inorganic Syntheses . tape 4 . McGraw-Hill, Inc., 1953, pp. 150-152 (English).
4. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Dipole Moments, pp. 9-51.
5. ↑ Entry on arsenic compounds in the GESTIS substance database of the IFA , accessed on February 1, 2016 (JavaScript required)
6. ↑ Not explicitly listed in Regulation (EC) No. 1272/2008 (CLP) , but with the specified labeling it falls under the group entry arsenic compounds, with the exception of those named in this appendix in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA) on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
7. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-5.
8. ↑ ^{a b c d} G. Brauer (Ed.), Handbook of Preparative Inorganic Chemistry 2nd ed., Vol. 1, Academic Press 1963, p. 197.