Silver(I) fluoride

• Silver fluoride
• Silver Monofluoride

Yellow solid

Fixed

5.85 g · cm -3

435 ° C

1150 ° C.

Very well in water (about 1850 g · l-1 at 15.5 ° C)

Risk

0.01 mg · m-3

-204.6 KJ / mol

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Silver (I ) fluoride is the silver salt of the hydrofluoric acid. In contrast to the other halides of silver, it is less sensitive to light, very soluble in water and hygroscopic.

Production and representation

Silver (I ) fluoride, both of the elements silver, fluorine and silver (I / III ) oxide ( AgO ), silver ( I) oxide ( Ag2O ) and silver (I ) carbonate ( Ag2CO3 ), respectively obtained with hydrogen fluoride:

Properties

Such as silver chloride and silver bromide crystallizes AgF in the cubic NaCl type structure. Unlike the other silver halides AgF can from aqueous solutions as various hydrates crystallize ( AgF · H2O, AgF and AgF · · 2 H2O 4 H2O). With excess hydrofluoric acid to AgF · HF and AgF · 3 HF form. In one liter of water dissolve at room temperature (25 ° C) 1.8 kg AgF, with silberf (I ) fluoride dissociates into silver and fluoride ions:

The enthalpy of formation from the elements ( ΔHf ) is -204 kJ.

Use

Silver (I ) fluoride is mainly used in photography, where color films are coated with the sensitive especially in the UV range AgF. Silver (I ) fluoride is used as a mild and a fluoriding agent for element halides in the preparation of organofluoro compounds by the addition of fluorine to the double bonds. As an example the addition of AgF to Perfluoroalkene in acetonitrile may be mentioned, in which Perfluoroalkylsilber (I) compounds are formed: R- CF = CF2 AgF → R-( CF - CF3) Ag.

Also in the treatment of caries AgF or its diammine is used under the name Saforide (see links).

Safety

The use of silver (I ) fluoride is dangerous, because it reacts with, for example, silicon, titanium and calcium hydride under intense heat. In case of contact with boron and sodium, there is even a risk of explosion. Furthermore, it is corrosive to eyes and skin or inhaled into the lungs.