﻿Mixter 
  — 
  Oxides 
  and 
  Sulphides 
  of 
  Iron, 
  etc. 
  55 
  

  

  •Art. 
  YIII. 
  — 
  The 
  Heat 
  of 
  Formation 
  of 
  the 
  Oxides 
  and 
  Sul- 
  

   phides 
  of 
  Iron, 
  Zinc 
  and 
  Cadmium, 
  and 
  Ninth 
  Paper 
  on 
  

   the 
  Heat 
  of 
  Combination 
  of 
  Acidic 
  Oxides 
  with 
  Sodium 
  

   Oxide 
  • 
  by 
  W. 
  G. 
  Mixter. 
  

  

  [Contributions 
  from 
  the 
  Sheffield 
  Chemical 
  Laboratory 
  of 
  Yale 
  University.] 
  

  

  There 
  is 
  comparatively 
  little 
  known 
  about 
  the 
  heat 
  of 
  for- 
  

   mation 
  of 
  minerals 
  and 
  the 
  anhydrous 
  Oxides 
  and 
  sulphides 
  of 
  

   the 
  metals. 
  The 
  hydrated 
  compounds 
  have, 
  however, 
  been 
  

   more 
  fully 
  investigated. 
  The 
  object 
  of 
  the 
  work 
  was 
  the 
  

   study 
  of 
  some 
  minerals. 
  Some 
  other 
  compounds 
  were 
  also 
  

   investigated. 
  Except 
  in 
  a 
  few 
  cases 
  the 
  only 
  way 
  known 
  of 
  

   finding 
  the 
  heat 
  of 
  formation 
  of 
  a 
  mineral 
  is 
  by 
  fusion 
  with 
  

   sodium 
  peroxide. 
  The 
  method 
  involves 
  the 
  heat 
  effect 
  of 
  a 
  

   mineral 
  and 
  its 
  components 
  reacting 
  with 
  the 
  peroxide. 
  

  

  The 
  Oxides 
  of 
  Iron. 
  

  

  The 
  heat 
  of 
  formation 
  of 
  the 
  oxides 
  of 
  iron 
  has 
  been 
  deter- 
  

   mined 
  in 
  the 
  present 
  investigation 
  by 
  the 
  sodium 
  peroxide 
  

   method, 
  and 
  that 
  of 
  the 
  magnetic 
  oxide 
  by 
  burning 
  the 
  metal 
  

   in 
  oxygen. 
  Two 
  lots 
  of 
  sodium 
  peroxide 
  were 
  used, 
  one 
  of 
  

   which 
  gave 
  with 
  1 
  gram 
  of 
  rhombic 
  sulphur 
  5270 
  c 
  and 
  the 
  

   other 
  5240 
  c 
  , 
  and 
  hence 
  different 
  heat 
  effects 
  of 
  sulphur 
  are 
  

   given 
  in 
  the 
  tables 
  of 
  results. 
  The 
  peroxide 
  was 
  passed 
  

   through 
  a 
  -| 
  mm 
  mesh 
  and 
  only 
  the 
  fine 
  powder 
  used, 
  since 
  it 
  

   gives 
  quicker, 
  combustion 
  and 
  consequently 
  higher 
  temper- 
  

   atures 
  than 
  the 
  coarse 
  powder. 
  After 
  completing 
  a 
  series 
  of 
  

   determinations, 
  the 
  work 
  was 
  repeated 
  with 
  new 
  preparations 
  

   except 
  in 
  case 
  of 
  ferrous 
  oxide. 
  For 
  brevity 
  both 
  series 
  are 
  

   put 
  together 
  in 
  the 
  tables. 
  

  

  Iron. 
  — 
  The 
  metal 
  was 
  obtained 
  by 
  heating 
  ferrous 
  oxalate 
  

   gradually 
  in 
  hydrogen 
  to 
  a 
  red 
  heat. 
  When 
  cold 
  it 
  was 
  

   passed 
  through 
  a 
  J 
  mm 
  mesh 
  and 
  heated 
  again 
  in 
  hydrogen. 
  

   The 
  preparation 
  is 
  indicated 
  as 
  u 
  A." 
  The 
  determination 
  of 
  

   iron 
  as 
  ferric 
  oxide 
  gave 
  99*9 
  per 
  cent. 
  The 
  sample 
  contained 
  

   a 
  trace 
  of 
  carbon. 
  Preparation 
  a 
  B," 
  containing 
  99'8 
  per 
  cent 
  

   of 
  iron, 
  was 
  from 
  the 
  reduction 
  of 
  pulverulent 
  ferric 
  oxide 
  by 
  

   hydrogen. 
  Both 
  lots 
  of 
  iron 
  were 
  free 
  from 
  hydrogen 
  and 
  

   yielded 
  no 
  water 
  when 
  burned 
  in 
  oxygen. 
  

  

  In 
  the 
  following 
  experiments 
  U 
  A" 
  was 
  used 
  in 
  1, 
  2 
  and 
  3, 
  

   and 
  u 
  B"in 
  4, 
  

  

  A 
  little 
  iron 
  remained 
  unburned 
  in 
  3, 
  hence 
  the 
  result 
  is 
  not 
  

   included 
  in 
  the 
  final 
  value, 
  1719 
  C 
  . 
  For 
  2 
  gram 
  atoms 
  of 
  iron 
  

   reacting 
  with 
  sodium 
  peroxide 
  it 
  is 
  1719 
  c 
  X 
  111-68 
  == 
  192000 
  c 
  . 
  

  

  