Am.  Jour.  Pharm. 
March,  1887. 
Bismuth  Oxyiodide. 
119 
tion  of  nitric  acid.  The  excess  of  Bi203,  70*70 — 66*36  or  4  34  per 
cent.,  is  due  to  the  presence  of  an  equivalent  quantity  of  BiON03, 
which  gives  81'25  per  cent.,  Bi203. 
The  salts  used  in  the  preparation  were  carefully  tested  for  impur- 
ities and  were  found  to  be  pure,  so  that  BiOX03  is  the  only  possible 
contamination. 
From  the  percentages  of  oxides  can  be  calculated  the  percentage  of 
BiOI  and  BiON03  in  the  compound. 
A=l  part  of  the  preparation. 
B=Bi203  from  one  part  0*707 
I=Bi203     "     "     "   BiOI  0*6636 
N=Bi203    "     "     "  BiONOs  0*8125 
x  and  y  represent  unknown  quantities  of  BiON03  and  BiOI  respec- 
tively.   Then  x+y=A  and 
x=|=?  or  0-2914=29*14  per  cent.  BiOX03 
y=A— x  or  0*7086=70*86  per  cent.  BiOI. 
By  dividing  the  percentage  composition  by  the  molecular  weights 
of  the  salts,  the  figures  1*01  and  2*009  are  gotten,  showing  that  the 
compound  is  composed  of  one  molecule  BiOX03  and  two  molecules 
BiOI.  This  explains  for  only  two-thirds  of  the  potassium  iodide  taken 
entering  into  the  reaction,  which  can  now  be  written, 
3  BiONOs+2  KI=BiON03(BiOI)2-h2  KX03,  and 
864        331*2  993*2  202 
by  a  calculation  as  to  the  yield  of  BiON03(BiOI)2  from  10  gm. 
BiOX03  there  is  gotten  11*495  gin.  The  quantity  obtained  (Speci- 
men A2)  was  11*495  gm.,  agreeing  with  the  above  figures. 
The  above  reaction  occurs,  no  matter  how  great  the  excess  of  KI 
used,  and  if  the  resulting  product  be  thoroughly  washed  and  boiled 
with  an  additional  quantity  of  KI,  it  only  slightly  deepens  in  color 
(Specimen  A3),  without  assuming  the  color  and  crystalline  form  so 
characteristic  of  pure  BiOI. 
Thinking  that  BiOI  could  be  made  by  the  first  reaction  when 
carried  out  under  pressure,  the  following  experiments  were  made: 
1.  5  gm.  BiOXOs  and  2  gm.  KI  with  10  cc.  water, 
2.  5  gm.  BiOX03  and  3  gm.  KI  with  10  cc.  water, 
3.  5  gm.  BiOXOs(BiOI),  and  3  gm.  KI  with  10  cc.  water 
were  heated  in  sealed  tubes  for  two  hours  at  a  temperature  of  150c  C. 
On  examining  the  products,  they  were  not  found  to  differ  from  those 
