70 



Mr. G. Gore on Fluoride of Silver. 



[Dec. 7, 



stances in general; out of 132 substances only 14 were dissolved, and not 

 a single one exhibited signs of strong chemical action. 



III. " On Fluoride of Silver.— Part III." By G. Gore, F.R.S. 

 Received October 6, 1871. 



(Abstract.) 



In this communication the author has finally shown that the action of iodine, 

 under the influence of heat (including the process described by Kammerer, 

 Phil. Mag. 1863, vol. xxv. p. 213, for the isolation of fluorine), does not 

 liberate uncombined fluorine, but produces fluoride of iodine and iodide of 

 silver, a double salt, composed of iodide of silver and fluoride of platinum, 

 being produced at the same time by corrosion of the platinum vessels, if 

 the temperature approaches a red heat. 



The fluoride of iodine produced is a highly volatile and colourless liquid, 

 does not corrode mercury or red-hot platinum, corrodes glass at 60° Fahr., 

 and crystals of silicon at a red heat, also platinum in contact with argentic 

 fluoride in a state of fusion ; it instantly turns a deal splint black, fumes 

 powerfully in the air, and is decomposed with violence by water into 

 hydrofluoric and iodic acids, in accordance with the following equation : — 

 IF 5 + 3H 2 0=5HF-|-HI03. It dissolves iodine, and is absorbed by that 

 substance ; it is also absorbed either by argentic fluoride or iodide when 

 those substances are cooled in its vapour, and may be expelled from them 

 at a red heat. Its vapour quickly darkens the colour of a deal splint, and 

 very gradually turns paraffin brown. 



The platinum vessels in which the reaction with iodine was effected 

 were considerably corroded (but less so than when bromine or chlorine 

 were employed), and many expensive vessels were rendered useless by this 

 cause during the experiments. 



No chemical change occurred on heating argentic fluoride to redness 

 with pure carbon. 



By heating this fluoride to redness in a current of dried coal-gas, it was 

 wholly reduced to metallic silver, hydrofluoric acid and tetrafluoride of 

 carbon being evolved. 



In liquid cyanogen, argentic fluoride neither dissolved nor suffered che- 

 mical change ; but at a low red heat, in a current of dry cyanogen gas, it 

 was entirely reduced to metal, either nitrogen and tetrafluoride of carbon, 

 or fluoride of cyanogen being liberated. An aqueous solution of silver 

 fluoride was precipitated by passing a prolonged current of cyanogen gas 

 through it. Fluoride of silver was also decomposed by fusion with para- 

 cyanogen. 



Argentic fluoride was not dissolved or chemically changed by immer- 

 sion in anhydrous liquified hydrocyanic acid ; but by passing the dry acid 

 in vapour over the red-ho,t salt, the latter was decomposed and metallic 



