464' 
Iodide  of  Ammonium. 
Am.  Jour.  Pharm. 
Sept.,  1889. 
prepared  without  oxidation  taking  place  ;  in  this  case  the  U.  S.  P. 
should  adopt  at  least  the  specific  gravity  and  neutralization  deter- 
minations as  tests  of  purity,  the  former,  however,  depending  much 
upon  the  process  of  preparation. 
IODIDE  OF  AMMONIUM. 
A  SIMPLE  METHOD  OF  DECOLOKIZING  WHEN  DECOMPOSED.1 
By  John  C.  Falk,  Ph.  G. 
Iodide  of  ammonium,  as  is  well  known  to  all  pharmacists,  is  a  very 
unstable  compound,  the  ammonium  very  easily  dissociating  from  its 
union  with  the  haloid  element  iodine. 
This  decomposition  with  the  resultant  coloration  from  a  snow- 
white  salt  to  a  yellow  or  even  dark-brown — depending  on  the  amount 
of  liberated  iodine  present,  is  an  occurrence  seen  in  nearly  every 
pharmacy.  In  this  condition  the  chemical  is,  of  course,  unfit  for  use ;  and, 
as  the  small  quantities  usually  on  hand  in  the  stores  do  not  justify  the 
trouble  and  expense  of  manipulating  in  the  customary  methods,  such 
a  spoiled  salt  is  generally  thrown  away  or  set  aside,  and  a  fresh  supply 
obtained. 
The  pharmacopoeial  process  for  the  recovery  of  decolorized  iodide  of 
ammonium  is  to  wash  it  with  stronger  ether,  filter  off  the  latter,  and 
rapidly  drying  the  salt. 
R.  Bother  recommends  treating  the  salt  with  sulphurous  acid  and 
ammonia,  and  then  drying  on  a  water  bath.  Both  these  methods 
are  somewhat  troublesome  to  carry  out,  particularly  when  the  amount 
of  material  is  small  (say,  one  or  two  ounces)  while  the  pharmacopoeial 
directions  are  very  apt  to  result  in  an  expensive  product  if  extreme 
care  is  not  taken  in  the  use  of  the  ether. 
Having  several  small  lots  of  decomposed  iodide  of  ammonium  come 
into  my  hands  during  the  past  year,  it  occurred  to  me  that  they  might 
be  redeemed  in  a  manner  that  I  have  not  yet  seen  in  print.  This  con- 
sists simply  of  placing  a  lump  of  carbonate  of  ammonium  into  the 
bottle  and  allowing  it  to  remain  there  until  the  salt  has  regained  its 
normal  whiteness ;  this  may  require  from  several  days  to  as  many 
weeks,  the  time  being  dependent  upon  the  amount  of  material  and  the 
degree  of  decomposition  it  has  undergone.    The  ammonia  that  is  con- 
1  Eead  before  the  Missouri  State  Pharmaceutical  Association. 
