198  Silver  Chloride  with  Metallic  Chlorides.  {'^"Ypru^ilS""'- 
tion  commences  at  110 — 120°,  not  at  190°,  as  stated  by  Yvon,  and  the 
salt  fuses  at  290°  with  decomposition.  Towards  acids  and  solvents, 
the  crystallized  compound  behaves  like  that  precipitated  by  potassium 
iodide  ;  ammonia  and  caustic  alkalis  render  it  green,  and  on  heating 
convert  it  into  the  corresponding  alkaline  iodide  and  metallic  mer- 
cury. The  crystallized  iodide  is  less  sensitive  to  light  than  the  pre- 
cipitated yellow  compound,  which  rapidly  becomes  black  even  in  dif- 
fused daylight. 
When  mercurous  nitrate  solution  is  treated  with  bromine  under  simi- 
lar conditions,  small,  white,  nacreous,  tetragonal  scales  of  mercurous 
bromide  are  obtained,  and  the  same  compound  separates  in  yellow,  crys- 
talline spangles  when  an  alcoholic  or  aqueous  solution  of  bromide  is 
employed.  It  sublimes  at  340 — 350°  in  small  scales,  is  less  sensitive 
to  light  than  the  iodide,  dissolves  in  hot  sulphuric  acid  with  the  evolu- 
tion of  sulphurous  anhydride,  becomes  black  and  gradually  decom- 
poses when  heated  with  dilute  and  concentrated  hydrochloric  acid,  dis- 
solves slowly  in  hot  nitric  acid  (sp.  gr.  =  1.42),  and  decomposes  with 
the  formation  of  the  corresponding  bromides  when  treated  with  ammo- 
nia and  caustic  alkalis. — Jour.  Chem.  Soc,  1888,  111  ;  Berichte,  XX, 
2818. 
COMBINATION  OF  SILVER  CHLOEIDE  WITH  METAL- 
LIC CHLORIDES. 
By  M.  C.  Lea. 
If  hydrochloric  acid  is  mixed  first  with  ferric  chloride  and  then  with 
silver  nitrate,  the  silver  chloride  which  forms  is  not  white  but  buff- 
colored.  The  ferric  chloride  cannot  be  removed  by  washing,  and  is 
only  partially  removed  by  treatment  with  hydrochloric  acid.  The 
presence  of  the  minute  quantity  of  ferric  chloride  makes  the  silver 
chloride  remarkably  less  sensitive  to  light. 
Cobalt  chloride  and  hydrochloric  acid  give  a  silver  chloride,  which 
is  pink,  and  contains  cobalt ;  but  the  reduction  in  the  sensitiveness  to 
light  is  very  much  less  than  when  iron  is  present.  Nickel  and  manga- 
nese behave  similarly,  but  cupric  chloride  seems  to  have  no  tendency  to 
combine  with  silver  chloride.  The  tendency  of  gold  chloride  to  com- 
bine with  the  silver  chloride  is,  however,  well  marked,  and  the  pre- 
cipitate has  a  reddish  shade,  but  the  influence  on  the  sensitiveness  is  not 
