Am  Jour.  Piiarm.  \ 
August,  18^2.  J 
Chemical  Notes. 
CHEMICAL  NOTES. 
By  Prof.  Samuel  P.  Sadtler,  Ph.D. 
Inorganic  Chemistry.— Pernitric  Acid. — Hautefeuille  and. 
ChappuiSj  who  announced  the  fact,  some  time  ago,  that  when  the  elec- 
tric spark  is  passed  through  a  mixture  of  nitrogen  tetroxide  and 
oxygen,  the  red  color  of  the  mixture  disa})pears  and  a  colorless  gas 
remains,  have  still  further  investigated  the  matter.  They  find  that 
the  electric  spark  will  develop  the  same  compound  from  a  dry  mixture 
of  oxygen  and  nitrogen  gases.  That  the  new  compound  is  not  nitric 
oxide,  N2O5,  is  recognized  by  the  fact  that  it  cannot  be  gotten  crystallized 
or  in  the  solid  form  at  all,  as  nitric  oxide  readily  can  be.  Tliey  find, 
moreover,  that  this  new  compound  forms  up  to  a  maximum  amount 
from  the  action  of  the  spark  upon  the  mixture  of  gases,  and  after  that 
the  combination  just  made  is  broken  up  and  nitrogen  tetroxide  and 
free  oxygen  remain.  This  maximum  amount  is  dependent  upon  tem- 
perature, the  lower  the  temperature  the  larger  being  the  amount., 
They  do  not,  as  yet,  propose  any  formula  for  it.  —  Comptes  Rendus,. 
94,1111. 
On  the  Rare  Metals  of  the  Cerium,  and  Yttrium  Groups. — Roscoe  has 
recently  made  a  study  of  the  mixture  of  rare  earths  from  samarskite) 
with  a  view  of  determining  whether  De  la  Fontaine's  philippium  has 
any  real  existence  or  not.  De  la  Fontaine  had  given,  as  one  charac- 
teristic of  the  supposed  element  the  fact  that  it  formed  a  well-crys- 
tallized formiate  distinct  from  that  of  terbium  or  yttrium.  Roscoe- 
finds  that  a  mixture  of  the  formiates  of  terbium  and  yttrium  can  crys- 
tallize in  the  single  forms  described  as  characteristic  of  philippium.. 
He  comes  to  the  same  conclusion  with  regard  to  the  non-existence  of 
philippium  from  a  spectroscopic  view  of  the  several  oxides,  and  from  the 
standpoint  of  Mendelejeflf's  periodic  system  of  the  elements  shows  that 
an  element  is  not  to  be  expected  in  the  position  of  philippium,  and 
with  the  properties  aeribed  to  it. — Ber.  Chem.  Ges.,  xv,  p.  1274. 
P.  T.  Cleve  publishes  a  note  on  didymium  and  a  supposed  new  ele- 
ment which  accompanies  it.  In  purifying  didymium  preparations,  he 
got  fractions  showing  a  variation  in  spectral  lines,  and  giving  for  the 
atomic  weight  of  didymium  values  varying  from  146  to  142.  The 
first  of  these  he  considers  as  pure  didymium,  and  the  last  to  be  con- 
taminated with  an  element  yet  to  be  isolated,  which  he  designatcis  pro- 
visionally  as  D\fi.—  Chem.  News,  Junc^  23,  p.  273. 
