ON  IODIDE  OF  SODIUM. 
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IODIDE  OF  SODIUM. 
Br  the  Editor. 
Among  the  new  remedies  (or  perhaps  old  remedies  in  new 
forms,)  is  iodide  of  sodium,  which  has  been  called  for  by  several 
physicians  in  this  city. 
It  may  be  economically  and  easily  made  by  the  following 
recipe  : 
Take  of  Iodine,  two  ounces, 
Iron  filings,  an  ounce, 
Carbonate  of  Soda,  in  crystals,  two  and  a  half  ounces. 
Water,  a  sufficient  quantity. 
Mix  the  iodine  with  six  fluidounces  of  water  in  a  flask,  add  the 
iron  filings,  and  agitate  them  together  till  the  reaction  ceases 
and  all  the  iodine  is  combined;  throw  the  whole  on  a  filter,  and 
when  the  solution  has  passed,  wash  the  filter  with  water  till  the 
whole  measures  a  pint.  Dissolve  the  carbonate  of  soda  in  half 
a  pint  of  water,  and  add  it  to  the  solution  of  iodide  of  iron,  till  it 
ceases  to  produce  a  precipitate  of  carbonate  of  iron  ;  then  heat 
the  mixture  nearly  to  the  boiling  point,  filter  and  wash  the  residue 
on  the  filter  with  half  a  pint  of  water,  and  add  it  to  the  filtered 
liquid.  Lastly,  evaporate  this  in  a  porcelain  capsule,  till  a  pellicle 
begins  to  form,  and  set  it  aside  to  crystallize  by  cooling.  Pour  off 
the  mother  liquid  from  the  crystals  when  formed,  and  again  evapor- 
ate and  crystallize. 
Iodide  of  sodium,  may  also  be  made  precisely  as  directed  for 
iodide  of  potassium  in  the  United  States  Pharmacopoeia,  substitu- 
ting caustic  soda  for  caustic  potassa ;  but  independent  of  the 
fact,  that  pure  caustic  soda  is  expensive,  it  is  necessary  in  de- 
oxidizing the  iodate  of  soda  to  avoid  contact  of  air,  else  there  is 
a  loss  of  iodine  with  the  formation  of  carbonate  of  soda. 
Iodide  of  sodium  obtained  as  above,  by  the  cooling  of  a  hot  solu- 
tion, crystallizes  in  white  anhydrous  cubes.  When  formed  by 
spontaneous  evaporation  it  contains  4  equiv.  of  water  of  crystal- 
lization. The  crystals  are  striated  oblique  rhombic  prisms,  melt 
when  gently  warmed,  and  on  being  heated  lose  their  water,  leaving 
dry  iodide  of  sodium.  The  hydrated  iodide  is  more  stable  when 
exposed  to  the  air  than  the  anhydrous  salt,  but  is  more  deliques- 
cent, and  very  soluble.  (Ghnelin.) 
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