84 
Mercurammonium  Chlorides, 
Am.  Jour.  Pharm. 
Feb.,  1888. 
of  KOH,  while  the  compound  resulting  from  its  decomposition 
will  not. 
5.  Action  of  boiling  water.  This  reacts  only  with  I.  and  II.,  and 
is  explained  under  lY.  If  a  pure  NHgHgCl  is  boiled  with  water  a 
whitish  product  is  obtained,  while  if  the  NHgHgCl  is  contaminated 
with  either  mercurdiammonium  chloride  or  ammonium  chloride,  a 
pale  or  deeper  yellow  is  obtained,  depending  upon  the  quantity 
present. 
6.  Aciion  of  potassium  iodide.  I.  and  II.  changed  at  once  to  a  yel- 
low or  red  color.  III.  to  a  purple,  IV.  slowly  to  a  brown.  On  heat- 
ing they  finally  took  a  purple  color,  while  ammonia  was  freely 
given  off. 
7.  Action  of  sodium  thiosidphate.  Were  all  slowly  soluble  in  a  cold 
solution  and,  on  boiling,  deposited  black  mercuric  sulphide.  Am- 
monia vapors  were  evolved. 
8.  Action  of  ammonium  chloride.  The  samples  were  soluble  in  a 
boiling  solution  of  the  above,  III.  and  IV.  first  becoming  pure  white 
precipitates,  showing  the  change  of  the  dimercurammonium  chloride 
into  either  the  fusible  or  infusible  white  precipitates ;  the  former  is  more 
apt  to  be  the  one,  for  the  ammonium  chloride  was  in  excess.  This 
change  takes  place  simply  by  the  addition  of  one  or  three  molecules 
of  ammonium  chloride. 
NHg2Cl+NH4Cl-=2  NH^HgCl. 
NHg^Cl+S  NH,C1=2  (NH3Cl)2Hg. 
9.  Astion  of  acetic  acid.  On  reading  over  the  tests  of  the  U.  S.  P. 
one  is  apt  to  receive  the  impression  that  the  officinal  ammoniated  mer- 
cury is  easily  soluble  in  the  above  acid,  but  such  is  not  so.  All  of  the 
specimens  examined  were  but  sparingly  soluble,  I.  and  II.  dissolved 
upon  moderate  warming  in  a  considerable  quantity  of  acid ;  but  if 
this  solution  is  boiled  a  very  peculiar  reaction  occurs,  the  mixture  be- 
comes turbid,  and  there  is  precipitated  from  the  boiling  solution  a 
white  granular  powder.  This,  after  filtration  and  washing,  was  found 
to  turn  dark  on  boiling  with  hydrochloric  acid,  caused  by  separation 
of  metallic  mercury,  and  the  acid  solution,  after  filtering,  showed  the 
presence  of  mercuric  chloride  ;  tested  by  the  addition  of  ammonium 
and  potassium  hydrates  the  white  powder  turned  black.  These  tests 
prove  the  nature  of  the  precipitate ;  it  is  mercurous  chloride,  or  calo- 
mel. The  filtrate  from  the  calomel  contained  a  trace  of  mercurous 
salt,  as  a  turbidity  was  occasioned  by  the  addition  of  [hydrochloric 
