Mr.  G.  Gore  on  Fluoride  of  Silver.  383 
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  ap- 
proaches 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  accord- 
ance with  the  following  equation  :— IF5  +  3H20=5HF+HI03.  It 
dissolves  iodine,  and  is  absorbed  by  that  substance ;  it  is  also  ab- 
sorbed 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  bro- 
mine 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  red- 
ness 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  te- 
trafluoride  of  carbon  being  evolved. 
In  liquid  cyanogen,  argentic  fluoride  neither  dissolved  nor  suffered 
chemical  change ;  but  at  a  low  red  heat,  in  a  current  of  dry  cya- 
nogen gas,  it  was  entirely  reduced  to  metal,  either  nitrogen  and  te- 
trafluoride  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  paracyanogen. 
Argentic  fluoride  was  not  dissolved  or  chemically  changed  by 
immersion  in  anhydrous  liquified  hydrocyanic  acid  ;  but  by  passing 
the  dry  acid  in  vapour  over  the  red-hot  salt,  the  latter  was  decom- 
posed and  metallic  silver  liberated.  Aqueous  hydrocyanic  acid  readily 
precipitated  a  solution  of  argentic  fluoride. 
Fluoride  of  silver  was  not  decomposed  by  heating  it  to  redness 
in  an  atmosphere  of  carbonic  oxide  or  carbonic  acid  gases ;  but  by 
prolonged  passage  of  the  mixed  gases  through  an  aqueous  solution 
of  the  salt,  a  brown  precipitate,  soluble  in  aqueous  hydrofluoric  acid, 
was  produced. 
By  fusing  the  fluoride  in  a  current  of  vaporous  terchloride  of 
carbon,  it  was  wholly  converted  into  argentic  chloride,  the  vessels 
being  much  corroded,  and  an  insoluble  double  salt  of  platinum  and 
silver  formed.  Similar  results  took  place  on  using  tetrachloride  of 
carbon.  Silver  fluoride  was  insoluble,  and  remained  unchanged  in 
liquid  tetrachloride  of  carbon  at  60°  Fahr. ;  and  terchloride  or  tetra- 
chloride of  carbon  had  no  chemical  effect  upon  an  aqueous  solution 
