Syrup  of  Ferrous  Iodide. 
Am.  Jour.  Pharm: 
April,  1876. 
The  sulphur  precipitates  in  minute  division  and  remains  suspended  in 
the  syrup,  rendering  it  turbid  and  nearly  as  unsightly  as  before  the 
treatment  with  the  hyposulphite. 
About  two  years  ago,  I  had  some  syrup  of  ferrous  iodide  which  had 
changed  color,  and  desiring  to  restore  it  to  its  original  greenish  tint,  I 
did  not  feel  disposed  to  use  hyposulphite  of  sodium,  because  of  the 
precipitate  of  sulphur  already  mentioned.  In  thinking  upon  the  matter, 
I  concluded  that  hypophosphorous  acid,  having  like  affinity  for  oxygen, 
would  perform  a  similar  work  to  that  effected  by  the  hyposulphite.  I, 
therefore,  added  to  a  sample  of  my  colored  syrup  a  few  drops  of 
hypophosphorous  acid  (P.  &  W.'s),  shook  the  bottle,  and  allowed  it  to 
stand  a  short  time,  and  examined  it,  when  it  was  found  to  have  re- 
sumed the  proper  color,  and  the  syrup  was  perfectly  clear;  I  then 
treated  the  whole  of  the  discolored  syrup  with  hypophosphorous  acid 
with  like  satisfactory  results.  The  chemistry  of  these  reactions  will 
be  readily  understood  by  the  following  equations  : 
HPH202+I2+H20=2HI+H3POs,  or 
HPH202+I4+2H20=4HI+H3P04,  or 
HPH202-f2Fe2OI4=4FeI2+H3P04. 
There  are  on  the  table  two  small  bottles  of  syrup  of  ferrous  iodide 
taken  from  one  lot ;  to  one  has  been  added  a  few  drops  of  hypophos- 
phorous acid,  and  its  color  is  normal,  the  other  is  exhibited  for  com- 
parison, showing  the  change  of  color. 
If,  after  making  syrup  of  ferrous  iodide,  it  is  observed  that  it  has  a 
slight  olive  tint  in  place  of  the  pure  pale  green  ;  this  may  be  removed 
by  the  addition  of  a  small  quantity  of  solution  of  hypophosphorous  acid, 
and  upon  introducing  some  clean,  small  nails  or  wire,  and  allowing  it  to 
stand  awhile,  small  bubbles  of  gas  (hydrogen)  will  be  observed  accumu- 
lating on  the  surface  of  the  nails,  and  if  the  bottle  is  moved  these  will 
pass  up  through  the  syrup ;  the  nails  react  with  the  hydriodic  acid 
(formed  as  explained  in  the  foregoing  equations),  with  the  liberation  of 
hydrogen  and  production  of  ferrous  iodide.  Syrup  thus  treated  is  not 
prone  to  become  discolored  soon  again. 
It  is  not  my  intention  to  propose  that  hypophosphorous  acid  be  in- 
troduced as  a  regular  constituent  of  syrup  of  ferrous  iodide,  for  I  am 
opposed  to  tampering  with  officinal  formulas  ;  but  I  do  suggest  it  as  a 
remedy  for  the  difficulty,  when  syrup  of  the  iodide  of  iron  changes 
color. 
