Am.  Jour.  Pharm. 
Feb.,  1888. 
Mercur ammonium  Chlorides. 
83 
The  tests  applied  to  the  above  preparations  were  : 
1.  Color.  I.  and  II.  were  white;  III.  white  with  tinge  of  yel- 
low ;  IV.  yellow. 
2.  Fusibility.  Of  the  specimens  made  only  those  in  class  II. 
were  fusible ;  of  these,  e,  d  and  e  were  more  fusible  than  a  and  b, 
which  were  only  partially  so.  It  has  been  stated  that  owing  to  the 
decomposition  of  infusible  white  precipitate  by  washing  with  water, 
the  U.  S.  Pharmacopoeia  did  not  require  thorough  washing  and  that 
if  the  ammonium  chloride  remaining  in  the  product  equalled  7  to  8 
per  cent,  the  mixture  would  become  partially  or  wholly  fusible.  The 
presence  of  this  quantity  of  ammonium  chloride  would  be  sufficient 
to  form  40  to  50  per  cent,  fusible  precipitate  from  the  infusible.  The 
amount  of  ammonium  chloride  formed  in  the  U.  S.  Pharmacopoeia 
process  is  somewhat  less  than  2  parts,  and  as  there  are  over  200  parts 
of  liquid  (water)  present  it  should  be  possible  to  remove  at  least  three- 
fourths  of  this  without  washing.  By  washing,  at  least  one-half  of 
the  remaining  liquid  should  be  displaced,  and,  without  allowing 
for  the  additional  quantity  removed  by  pressing  between  bibulous 
paper,  there  is  left  only  one-eighth  of  the  original  quantity  of  ammo- 
nium chloride,  which  is  0.25  of  1  part,  or,  expressed  in  percentage 
to  the  yield  of  white  precipitate,  2.6  per  cent.  By  careful  washing 
and  drying  between  filter  paper  it  should  be  possible  to  bring  this 
to  less  than  1  per  cent.,  which  is  not  sufficient  to  show  any  signs  of 
fusion. 
3.  Solubility  in  hydrochloric  acid.  Common  to  all,  slowly  in  the 
oold,  easily  on  application  of  heat. 
4.  Action  of  potassium  hydrate.  This  caused  the  evolution  of 
ammonia  from  I.  and  II.,  and  a  yellow  color  in  I.,  II.  and  III. 
No  odor  of  ammonia  was  perceptible  with  III.  and  IV.,  and 
litmus  paper  failed  to  indicate  more  than  traces ;  these  compounds 
do  not  decompose  into  ammonia,  mercuric  oxide  and  potassium 
chloride,  as  is  the  case  with  I.  and  II.,  but  are  changed  into  the 
hydrate  corresponding  to  the  chloride,  or  dimercurammonium  hydrate, 
the  chlorine  uniting  with  the  potassium  to  form  potassium  chloride. 
In  Attfield^s  Chemistry  is  the  statement  that  NH2HgCl  on  wash- 
ing was  changed  into  a  compound  of  mercurammonium  chloride 
and  mercuric  oxide  XHaHgCljHgO ;  on  examination  this  is 
seen  to  be  equal  to  NHg2Cl,H20,  but  I  doubt  its  correctness, 
as  mercurammonium  chloride  will  liberate  ammonia  on  addition 
