THE 
AMERICAN  JOURNAL  OF  PHARMACY. 
DECEMBER,    187  3. 
NOTES  ON  THE  TASTELESS  IRON  COMBINATIONS. 
By  E.  Rutter. 
Having  been  engaged  in  the  preparation  of  these  salts  since  their 
introduction  by  Mr.  Creuse,  of  Brooklyn,  in  May  last,  it  has  always 
been  an  object  with  me  to  ascertain  their  true  composition.  The 
theory  of  double  decomposition  falls  at  once  to  the  ground,  as  in 
that  case  one  molecule  of  ferric  salt  would  require  only  two  mole- 
cules of  alkaline  citrate ;  whereas  it  will  be  found  that  four  mole- 
cules of  the  latter  are  always  required  to  form  the  green  compound. 
Now  citric  acid,  as  is  well  known,  may,  under  certain  conditions,  be 
resolved  into  oxalic  and  acetic  acids,  and  the  similarity  of  color  to 
that  of  ferric  oxalate  led  me  to  suppose  that  the  reaction  might  con- 
sist in  the  splitting  up  of  the  organic  acid  and  the  formation  of  a 
double  oxalate  of  potassium  and  iron,  together  with  chloride,  iodide, 
or  phosphate  of  potassium,  according  to  which  salt  was  used.  Such, 
however,  is  not  the  case,  for  on  treating  the  green  compound  with 
excess  of  alkali,  filtering  out  the  iron,  and  adding  calcium  chloride 
to  the  filtrate,  a  precipitate  is  formed  which  is  freely  soluble  in  acetic 
acid,  and  cannot  therefore  be  calcium  oxalate.  This  theory  set  aside? 
the  only  one  tenable  seems  to  be  the  following  : 
Fe2T6+  4K3C6H507  =  6  KI  -f  2  (K3Fe'"2C6H507). 
that  is  the  formation  of  double  citrate  of  iron  and  potassium  together 
with  potassium  iodide.*    Believing  this  to  be  the  true  reaction,  I 
tried  the  experiment  of  mixing  potassic  and  ferric  citrates  in  equiva- 
*This  result  has  been  experimentally  proven  by  G.  F.  Dickman  in  The 
Pharmacist  for  September  ;  the  saline  residue  left  on  evaporating  the  green 
solution  yielded  to  alcohol  iodide  of  potassium. — Ed.  Am.  Journ.  Pharm. 
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