448 
Chemical  Notes. 
(  Am.  Jour.  Pharro. 
\      Sept.,  1879. 
platinum  and  palladium,  is  6*25.  Its  atomic  weight  has  been  found 
187*25.  In  its  chemical  properties  it  is  dificult  to  distinguish  from 
platinum. —  Chem.  News,  Aug.  1,  1879,  p.  57. 
Vapor  densities  of  Inorganic  Compounds. — Victor  and  Carl  Meyer  have 
continued  their  determinations  of  the  vapor  densities  of  inorganic  com- 
pounds, and  have  satisfactorily  established  the  formulas  in  several  im- 
portant disputed  cases.  Thus,  in  the  two  publications  recently  made 
by  them,  we  have  determinations  of  the  vapor  density  of  stannous 
chloride,  zinc  chloride,  ferric  chloride,  antimonous  acid,  cuprous  chlor- 
ide and  cadmium  bromide.  Stannous  chloride  might  have  the  formula 
Sn2Cl4,  or  it  might  be  SnCl2.    The  authors  find  as  follows: 
Calculated  Vapor-density.  Experimental  Vapor -density. 
For  Sn2Cl4,        .       .       .    13*06  Found  at  6i9°C,         .       .  12-85 
For  SnCl2,      .       .       .         6-53  Found  at  6g7°C,     .       .  13*08 
The  formula  is,  therefore,  undoubtedly  Sn2Cl4. 
Zinc  chloride  gave  the  following  results: 
Calculated  Vapor-density.  Experimental  Vapor- density. 
For  ZnCl2,       .        .        .    4-70  Found  at  89o°C,    .       .       .  4*5$ 
Found  at  907°C,        .       .  4*61 
The  formula  is,  therefore,  ZnCl2. 
Ferric  chloride,  although  generally  accepted  as  Fe2Cl6,  is  sometimes 
written  FeCl3,  and  it  was,  therefore,  quite  important  to  get  reliable 
determinations  of  its  vapor  density.  Deville  and  Troost  had  determined 
it  in  sulphur  vapor  at  447°C.  as  11*42  and  11*37,  the  theoretical  for 
Fe2Cl6  being  11*23.    The  results  obtained  by  the  authors  were: 
Calculated  Vapor-density.  Experimental  Vapor-density. 
For  Fe2Cl6        .       .       .    11*23  Found  at  447°C,         .       .  11-14 
Found  at  6i9°C,     .       .  iroi 
Their  result  agrees,  therefore,  with  those  of  Deville  and  Troost,  and 
fix  the  formula  as  Fe2Cl6. 
Ferrous  chloride  was  next  tried,  but  in  each  experiment  the  com- 
pound was  decomposed  by  the  heat  applied.  The  authors  hope,  how- 
ever, to  succeed  shortly  with  this  most  important  compound. 
Antimonous  acid  was  then  taken.  The  authors  had  previously  found 
that  arsenous  acid  had  the  molecular  formula  As4Ofi  instead  of  As2Os 
as  generally  accepted.  It  was  therefore  of  interest  to  see  if  antimo- 
nous acid  was  similarly  constituted,  or  if  it  had  the  simpler  formula 
Sb3Q3.    The  results  were: 
