Am'j5yri8Mfrm'}       Syrup  of  Hypophosphites  with  Iron.  359 
Fe  -  Py2 
II  I  (5) 
Ci  —  Ca 
But  if  one  equivalent  of  ferric  citrate  be  treated  in  solution  with 
two  equivalents  of  calcium  hypophosphite,  the  solution  contains  a 
grass-green  amorphous  compound,  which  may  be  obtained  in  scales 
and  is  represented  thus  : 
Ca  -  Py2 
I  I 
Ci  —  Fe  (6) 
I  I 
Ca  -  Py2 
It  will  be  seen  from  the  foregoing  results  that  the  compounds  repre- 
sented by  the  first,  third  and  fifth  constitutional  formulas  cannot  exist 
in  solution  with  a  free  hypophosphite  as  the  inevitable  result  will  be, 
the  formation  of  the  compounds  represented  by  the  second,  fourth  and 
sixth  formulas,  respectively.  It  is  also  found  that  if  a  hypophosphite 
be  added  to  a  solution  of  either  of  the  latter  compounds,  chemical 
union  does  not  take  place  and  the  solution  on  evaporation  will  deposit 
the  hypophosphite  in  crystals.  This  reaction  will  explain  the  forma- 
tion of  crystals  of  sodium  hypophosphite  in  addition  to  the  amorphous 
compound  on  dissolving  one  equivalent  of  ferric  hypophosphite  in  a 
solution  of  one  equivalent  of  sodium  citrate ;  and  the  similar  reaction 
attendant  on  the  use  of  potassium  citrate. 
It  is  evident,  therefore,  that  if  ferric  citrate  be  dissolved  in  a  solution 
of  an  excess  of  the  hypophosphites  of  calcium,  sodium  and  potassium, 
one  or  more,  perhaps  all  of  the  compounds  represented  by  the  second, 
fourth  and  sixth  graphic  formulas  will  be  formed.  The  absolute 
stability  and  free  solubility  of  these  compounds,  even  in  the  presence 
of  a  large  excess  of  free  hypophosphites,  and  the  fine  green  color  of  the 
solution  consequent  on  their  presence,  are  certainly  sufficiently  good 
reasons  for  the  recommendation  of  the  use  of  ferric  citrate  in  the  pre- 
paration of  syrup  of  hypophosphite  with  iron. 
In  addition  to  the  process  ordered  in  the  pharmacopoeia  for  the  pre- 
paration of  syrup  of  hypophosphites  which  consists  merely  in  solution, 
other  methods  are  in  vogue,  which  depend  on  double  decomposition, 
including  the  so-called  sulphate  and  carbonate  processes. 
Comments  on  the  process  ordered  in  the  pharmacopoeia  are  un- 
