﻿4:02 
  Kuzirian 
  — 
  Water 
  of 
  Crystallization 
  in 
  Sulphates. 
  

  

  like 
  silico-fluoricles. 
  Under 
  definite 
  conditions, 
  this 
  flux 
  seems 
  

   to 
  give 
  satisfactory 
  results, 
  a 
  correction 
  being 
  necessary 
  when 
  

   the 
  separated 
  metallic 
  oxide, 
  e. 
  g. 
  ferrous 
  oxide, 
  takes 
  up 
  atmos- 
  

   pheric 
  oxygen. 
  In 
  the 
  case 
  of 
  decomposable 
  sulphates, 
  how- 
  

   ever, 
  no 
  attempt 
  has 
  been 
  made 
  to 
  determine 
  their 
  water 
  of 
  

   crystallization, 
  while 
  retaining 
  all 
  of 
  the 
  acidic 
  oxide. 
  

  

  In 
  the 
  investigation 
  of 
  the 
  action 
  of 
  sodium 
  paratangstate 
  

   upon 
  some 
  salts, 
  containing 
  a 
  volatile 
  acid 
  radical, 
  both 
  in 
  pres- 
  

   ence 
  and 
  absence 
  of 
  superheated 
  steam, 
  described 
  in 
  previous 
  

   papers,* 
  it 
  has 
  been 
  shown 
  that 
  this 
  acidic 
  salt 
  is 
  able 
  to 
  expel 
  

   the 
  acidic 
  oxides 
  of 
  carbonates, 
  nitrates, 
  chlorides, 
  chlorates, 
  

   etc., 
  completely 
  and 
  with 
  great 
  ease. 
  But 
  sulphates 
  which 
  are 
  

   stable 
  on 
  simple 
  ignition, 
  for 
  example, 
  the 
  sulphates 
  of 
  sodium, 
  

   potassium, 
  barium 
  and 
  even 
  calcium 
  and 
  manganese, 
  do 
  not 
  

   lose 
  appreciably 
  their 
  sulphur 
  trioxide, 
  either 
  in 
  absence 
  or 
  in 
  

   presence 
  of 
  superheated 
  steam 
  on 
  fusion 
  with 
  the 
  paratung- 
  

   state. 
  For 
  example, 
  0*2 
  grin, 
  of 
  sodium 
  sulphate 
  on 
  fusion 
  

   with 
  the 
  paratungstate 
  did 
  not 
  lose 
  in 
  weight 
  at 
  all. 
  The 
  same 
  

   amount 
  of 
  manganous 
  sulphate 
  when 
  fused 
  with 
  the 
  same 
  flux 
  

   lost 
  only 
  0*0010 
  grm. 
  of 
  sulphur 
  trioxide. 
  Calcium 
  sulphate 
  

   on 
  similar 
  treatment 
  lost 
  only 
  0*0002 
  grm. 
  and 
  further 
  heating 
  

   did 
  not 
  occasion 
  further 
  loss. 
  The 
  explanation 
  is 
  that 
  the 
  

   basic 
  sodium 
  oxide 
  of 
  the 
  sodium 
  paratungstate 
  combines 
  with 
  

   volatile 
  sulphur 
  trioxide 
  of 
  the 
  sulphates 
  to 
  form 
  the 
  non- 
  

   volatile 
  sodium 
  sulphate. 
  The 
  presence 
  of 
  a 
  considerable 
  

   excess 
  of 
  the 
  acidic 
  tungsten 
  trioxide 
  apparently 
  does 
  not 
  

   influence 
  the 
  reaction. 
  

  

  The 
  following 
  may 
  serve 
  as 
  a 
  typical 
  representation 
  of 
  the 
  

   reaction 
  : 
  

  

  5MSO, 
  + 
  5Na 
  2 
  0.12W0 
  3 
  = 
  5Na 
  2 
  S0 
  4 
  + 
  5M0.12W0 
  3 
  

  

  Since 
  sodium 
  paratungstate 
  does 
  not 
  expel 
  the 
  volatile 
  sulphur 
  

   trioxide 
  from 
  sulphates, 
  it 
  should 
  be 
  capable 
  of 
  serving 
  a 
  use- 
  

   ful 
  purpose 
  as 
  a 
  flux 
  in 
  the 
  expulsion 
  of 
  the 
  water 
  of 
  crystal- 
  

   lization 
  of 
  sulphates 
  ordinarily 
  decomposable 
  by 
  heat 
  ; 
  and 
  

   any 
  sodium 
  tungstate 
  containing 
  less 
  of 
  this 
  acidic 
  oxide 
  

   should 
  be 
  similarly 
  serviceable. 
  In 
  the 
  preliminary 
  investiga- 
  

   tion 
  of 
  this 
  application 
  of 
  the 
  sodium 
  tungstates 
  a 
  nearly 
  neutral 
  

   sodium 
  tungstate 
  was 
  prepared,f 
  and 
  a 
  portion 
  of 
  the 
  dry 
  mate- 
  

   rial 
  was 
  weighed 
  and 
  placed 
  in 
  a 
  platinum 
  crucible, 
  a 
  weighed 
  

   portion 
  of 
  a 
  decomposable 
  sulphate 
  — 
  viz., 
  crystalline 
  copper 
  

  

  * 
  This 
  Journal 
  (4), 
  xxxi, 
  497; 
  xxxvi, 
  301, 
  305. 
  

  

  fin 
  order 
  to 
  purify 
  the 
  commercial 
  material, 
  which 
  ordinarily 
  contains 
  

   sodium 
  carbonate, 
  it 
  was 
  fused 
  in 
  a 
  large 
  platinum 
  dish 
  over 
  the 
  blast, 
  and 
  

   pure 
  tungstic 
  trioxide 
  was 
  added 
  until 
  carbon 
  dioxide 
  ceased 
  to 
  bubble 
  out. 
  

  

  