﻿Zirconium 
  with 
  Lithium, 
  Sodium 
  and 
  Thallium. 
  467 
  

  

  of 
  the 
  alkali 
  metals 
  with 
  a 
  still 
  higher 
  ratio 
  of 
  zirconium 
  than 
  

   was 
  the 
  case 
  with 
  caesium. 
  Such 
  was 
  not 
  the 
  case, 
  however. 
  

   The 
  salts 
  discovered 
  were 
  : 
  

  

  3T1F 
  . 
  ZrF 
  4 
  , 
  5T1F 
  . 
  3ZrF 
  4 
  . 
  H 
  2 
  0, 
  TIF 
  . 
  ZrF 
  4 
  and 
  Tl 
  F 
  . 
  ZrF 
  4 
  . 
  H 
  2 
  . 
  

  

  Two 
  of 
  these 
  three 
  types 
  of 
  thallous 
  salts 
  correspond 
  to 
  

   types 
  of 
  alkali-metal 
  salts, 
  while 
  one 
  type, 
  the 
  5 
  : 
  3, 
  is 
  a 
  new 
  

   one, 
  but 
  the 
  series 
  is 
  not 
  symmetrical 
  with 
  the 
  others 
  accord- 
  

   ing 
  to 
  the 
  atomic 
  weights. 
  

  

  Since 
  Marignac 
  had 
  described 
  but 
  one 
  sodium-zirconium 
  

   fluoride, 
  5iNaF.2ZrF 
  4 
  , 
  and 
  since 
  this 
  differs 
  from 
  all 
  other 
  

   alkaline 
  zirconium 
  fluorides, 
  we 
  have 
  undertaken 
  a 
  new 
  inves- 
  

   tigation 
  of 
  the 
  sodium 
  salts. 
  As 
  a 
  result, 
  we 
  have 
  fully 
  con- 
  

   firmed 
  Marignac's 
  results 
  as 
  to 
  the 
  5 
  : 
  2 
  salt, 
  which 
  is 
  the 
  one 
  

   most 
  readily 
  obtained, 
  and 
  we 
  have 
  succeeded 
  in 
  preparing 
  a 
  

   new 
  salt, 
  2NaF.ZrF 
  4 
  , 
  which 
  corresponds 
  to 
  the 
  most 
  usual 
  

   type 
  of 
  double 
  halogen 
  salts 
  of 
  tetravalent 
  elements. 
  It 
  is 
  

   evident, 
  however, 
  that 
  the 
  sodium 
  salts, 
  like 
  those 
  of 
  thallium, 
  

   do 
  not 
  form 
  a 
  symmetrical 
  series 
  with 
  the 
  others. 
  

  

  The 
  following 
  table 
  gives 
  a 
  list 
  of 
  the 
  sodium 
  and 
  thallium 
  

   salts 
  and 
  shows 
  the 
  positions, 
  "X" 
  of 
  the 
  other 
  compounds 
  

   prepared 
  by 
  Marignac 
  and 
  ourselves. 
  

  

  Ammo- 
  Potas- 
  

  

  Lithium 
  oium 
  Sodium 
  sium 
  Caesium 
  Thallium 
  

  

  Type. 
  salts. 
  salts. 
  salts. 
  salts. 
  salts. 
  salts. 
  

  

  (Mangnac) 
  (Marignac.) 
  

  

  4:1 
  X 
  ._ 
  .. 
  

  

  3:1 
  .. 
  X 
  X 
  .. 
  3TlF.ZrF 
  4 
  

  

  5:2 
  ._ 
  ._ 
  5XaF.2ZrF 
  4 
  

  

  2:1 
  X 
  X 
  . 
  2NaF.ZrF 
  4 
  X 
  X 
  

  

  5:3 
  .. 
  __ 
  5TlF.3ZrF,.HO 
  

  

  1:1 
  .. 
  .. 
  X 
  X 
  

  

  2:3 
  .. 
  .. 
  .. 
  X 
  

  

  TlF.ZrF 
  4 
  

   TlF.ZrF,.H„0 
  

  

  While 
  our 
  investigation 
  has 
  shown 
  that 
  the 
  rule' 
  for 
  the 
  vari- 
  

   ation 
  of 
  the 
  types 
  with 
  the 
  atomic 
  weights 
  applies 
  only 
  par- 
  

   tially 
  to 
  the 
  zirconium 
  double 
  fluorides, 
  we 
  have 
  shown 
  at 
  

   least 
  that 
  the 
  variety 
  of 
  types 
  is 
  remarkable 
  and 
  it 
  is 
  also 
  

   noticeable 
  that 
  the 
  ratios 
  are 
  nearly 
  the 
  simplest 
  that 
  can 
  exist 
  

   in 
  such 
  number 
  between 
  the 
  extreme 
  limits 
  4 
  : 
  1 
  and 
  2 
  : 
  3. 
  

  

  Preparation. 
  — 
  Thallium 
  fluoride 
  was 
  prepared 
  by 
  dissolving 
  

   the 
  metal 
  in 
  sulphuric 
  acid, 
  adding 
  an 
  excess 
  of 
  baryta 
  water, 
  

   Altering 
  and 
  passing 
  carbonic 
  acid 
  into 
  the 
  hot 
  solution. 
  The 
  

   filtrate 
  from 
  this 
  precipitation 
  was 
  evaporated 
  and 
  treated 
  with 
  

   hydrofluoric 
  acid 
  in 
  excess. 
  The 
  salts 
  were 
  prepared 
  by 
  mix- 
  

   ing 
  the 
  acid 
  solutions 
  of 
  the 
  fluorides 
  in 
  varying 
  proportions, 
  

   evaporating 
  and 
  cooling 
  to 
  crystallization. 
  The 
  salts 
  were 
  

  

  