Silver(I) fluoride

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Silver(I) fluoride
Names
IUPAC name
Silver(I) fluoride
Other names
Argentous fluoride
Silver monofluoride
Identifiers
3D model (
JSmol
)
ECHA InfoCard
100.028.996 Edit this at Wikidata
RTECS number
  • VW4250000
UNII
  • [Ag+].[F-]
Properties
AgF
Molar mass 126.8666 g·mol−1
Appearance yellow-brown solid
Density 5.852 g/cm3 (15 °C)
Melting point 435 °C (815 °F; 708 K)
Boiling point 1,159 °C (2,118 °F; 1,432 K)
85.78 g/100 mL (0 °C)
119.8 g/100 mL (10 °C)
179.1 g/100 mL (25 °C)
213.4 g/100 mL (50 °C)[1]
Solubility 83g/100 g (11.9 °C) in hydrogen fluoride
1.5g/100 mL in methanol(25 °C)[2]
−36.5·10−6 cm3/mol
Structure
cubic
Thermochemistry
48.1 J/mol·K[1]
83.7 J/mol·K[1]
Std enthalpy of
formation
fH298)
-206 kJ/mol[1]
-187.9 kJ/mol[1]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Corrosive
GHS labelling:[4]
GHS05: Corrosive
Danger
H314
P260, P280, P303+P361+P353, P304+P340, P305+P351+P338, P310[3]
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
3
0
0
Safety data sheet (SDS) External SDS
Related compounds
Other anions
Silver(I) chloride

Silver(I) bromide

Silver(I) iodide

Silver(I) astatide

Other cations
Copper(I) fluoride
Gold(I) fluoride
Related compounds
Silver subfluoride
Silver(II) fluoride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Silver(I) fluoride is the

.

The hydrates of AgF present as colourless, while pure anhydrous samples are yellow.[5]: 150 

Preparation

High-purity silver(I) fluoride can be produced by the heating of silver carbonate to 310 °C (590 °F) under a hydrogen fluoride environment, in a platinum tube:[6]: 9 

Laboratory routes to the compound typically avoid the use of gaseous hydrogen fluoride. One method is the thermal decomposition of silver tetrafluoroborate:

In an alternative route,

silver(I) oxide is dissolved in concentrated aqueous hydrofluoric acid, and the silver fluoride is precipitated out of the resulting solution by acetone.[6]
: 10 

Properties

Structure

The structure of AgF has been determined by

Non-stochiometric behaviour is exhibited by all three polymorphs under extreme pressures.[13]: 939 [11]
: 7947 

Spectroscopy

Silver(I) fluoride exhibits unusual optical properties. Simple electronic band theory predicts that the fundamental exciton absorption for AgF would lie higher than that of AgCl (5.10 eV) and would correspond to a transition from an anionic valence band as for the other silver halides. Experimentally, the fundamental exciton for AgF lies at 4.63 eV.[14]: 2604  This discrepancy can be explained by positing transition from a valence band with largely silver 4d-orbital character.[10]: 563  The high frequency refractive index is 1.73(2).[8]: 3737 

Photosensitivity

In contrast with the other

dihydrate is.[15]: 286 [5]: 150  With this and the material's solubility in water considered, it is unsurprising that it has found little application in photography but may have been one of the salts used by Levi Hill in his "heliochromy",[16] although a US patent for an experimental AgF-based method was granted in 1970.[17]

Solubility

Unlike the other silver halides, AgF is highly

soluble in water (1800 g/L), and it even has some solubility in acetonitrile. It is also unique among silver(I) compounds and the silver halides in that it forms the hydrates AgF·(H2O)2 and AgF·(H2O)4 on precipitation from aqueous solution.[18]: 1185 [19] Like the alkali metal fluorides, it dissolves in hydrogen fluoride to give a conducting solution.[20]

Applications

Organic synthesis

Silver(I) fluoride finds application in

alkyl halides under mild conditions.[2] An example is given by the following reaction:[22]

Another organic synthetic method using silver(I) fluoride is the BINAP-AgF complex catalyzed enantioselective protonation of silyl enol ethers:[23]: 1546 

Inorganic synthesis

The reaction of silver acetylide with a concentrated solution of silver(I) fluoride results in the formation of a chandelier-like [Ag10]2+ cluster with endohedral acetylenediide.[24]

Tetralkylammonium fluorides can be conveniently prepared in the laboratory by the reaction of the tetralkylammonium bromide with an aqueous AgF solution.[25]: 430 

Other

It is possible to coat a silicon surface with a uniform silver microlayer (0.1 to 1 μm thickness) by passing AgF vapour over it at 60–800 °C.[26] The relevant reaction is:

Multiple studies have shown silver(I) fluoride to be an effective

silver diamine fluoride (Ag(NH3)2F) is now more commonly used.[30]: 26  Preparation is by the addition of ammonia to aqueous silver fluoride solution or by the dissolution of silver fluoride in aqueous ammonia.[31]

References

  1. ^ a b c d e Chemister Chemical Database, Kiper Ruslan Anatolievich, 2002-15. URL: http://chemister.ru/Database/properties-en.php?dbid=1&id=1067
  2. ^ .
  3. ^ "Silver Fluoride". American Elements. Retrieved 2018-09-07.
  4. ^ Sigma-Aldrich Co., Silver(I) fluoride. Retrieved on 2014-05-08.
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  16. ^ Hill, Levi L. (1856). A treatise on heliochromy : or, The production of pictures, by means of light, in natural colors. Embracing a full, plain, and unreserved description of the process known as the hillotype, including the author's newly discovered collodio-chrome, or natural colors on collodionized glass ... Getty Research Institute. New York : Robinson & Caswell. p. 143.
  17. ^ US patent 3537855, "Photosensitive silver fluoride element", published 1971-11-3 
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  31. ^ US patent 3567823, Yokomizo Ichiro & Yamaga Reiichi, "Silver ammonia fluoride solution and method of its use", published 1971-2-12