Am.  Jour.  Pharm. 
April,  1876. 
Remarks  on  Iron  Salts. 
169 
monii  tartras,  ferri  et  potassii  tartras,  ferri  et  quiniae  citras,  ferri  et 
strychniae  citras  and  ferri  pyrophosphas.  There  are  others,  obtained  in 
the  same  form  as  these,  but  not  officinal.  I  propose  to  confine  my  re- 
marks to  the  above-mentioned,  exclusively. 
Except  pyrophosphate  of  iron,  they  all  have  oxide  of  iron  for  base. 
This  is  made  from  the  solution  of  tersulphate  of  iron,  by  precipitating 
with  water  of  ammonia.  To  obtain  a  perfect  oxide  of  iron  free  from 
discoloration,  a  solution  of  tersulphate  of  iron  is  used,  in  which  all 
sulphate  of  iron  is  perfectly  oxidized.  In  preparing  the  solution,  this 
is  ascertained  by  taking  a  small  quantity,  diluting  with  water,  and  add- 
ing water  of  ammonia  in  excess.  If  a  clear,  reddish-brown  precipitate 
results,  oxidation  is  complete,  but,  if  it  is  discolored,  brownish-black, 
with  dirty  gray,  nitric  acid  is  added  to  the  hot  solution,  drop  by  drop, 
until  the  disengagement  of  nitrous  acid  gas  ceases,  when  the  oxidation 
will  be  found  to  be  complete,  and  the  precipitate  obtained  without  dis- 
coloration. The  precipitated  oxide  of  iron  is  washed  until  the  wash- 
ings pass  nearly  tasteless,  or  if  wanted  perfectly  pure,  first  wash  with 
water,  and  finally  with  distilled  water,  until  the  washings  cease  to  pro- 
duce a  precipitate  with  chloride  of  barium. 
The  magma  of  oxide  ^of  iron  is  dissolved  in  citric  acid  at  a  temper- 
ature not  exceeding  1400  F.,  and  evaporated  at  the  same  temperature, 
to  form  citrate  of  iron.  This  salt  dissolves  with  difficulty  in  cold,  but 
more  readily  in  warm  water. 
Ammonio-citrate  of  iron  is  prepared  by  adding  a  sufficient  quantity  of 
water  of  ammonia  to  neutralize  the  acid  solution  of  citrate  of  iron. 
This  neutralization  renders  an  otherwise  difficultly  soluble  salt  readily 
soluble  in  cold  water. 
In  tartrate  of  iron  and  ammonium,  oxide  of  iron  is  dissolved  in  a 
neutralized  solution  of  bitartrate  of  ammonium.  The  "  Pharmacopoeia  " 
says,  "  slowly  soluble,"  which  is  so,  it  being  rather  slowly  soluble. 
Tartrate  of  iron  and  potassium  is  made  by  dissolving  oxide  of  iron 
in  the  free  tartaric  acid  of  bitartrate  of  potassium  or  cream  of  tartar. 
The  "  Pharmacopoeia  "  says,  "  wholly  soluble  in  water."  I  find  it, 
prepared  strictly  according  to  the  formula,  slowly  soluble  in  cold  water, 
the  solution  depositing  a  copious  precipitate. 
Citrate  of  iron  and  quinia  is  prepared  by  dissolving  a  certain  quan- 
tity of  quinia  in  solution  of  citrate  of  iron.  The  iC  Pharmacopoeia  " 
says  of  the  salt,  "  slowly  soluble  in  cold  water,"  which  is  in  truth  so  ; 
in  fact,  it  is  too  slowly  soluble. 
