﻿Rubidium, 
  Sodium 
  and 
  Lithium 
  with 
  Thallium. 
  401 
  

  

  3:2 
  Ccesium 
  Thallic 
  Chloride, 
  Os 
  s 
  Tl 
  2 
  Cl 
  r 
  — 
  The 
  conditions 
  

   under 
  which 
  this 
  salt 
  can 
  be 
  made 
  are 
  very 
  wide, 
  *5 
  to 
  29 
  g. 
  of 
  

   csesium 
  chloride 
  form 
  a 
  heavy 
  white 
  precipitate 
  when 
  added 
  to 
  

   a 
  solution 
  of 
  40 
  g. 
  of 
  thallic 
  chloride. 
  This 
  dissolves 
  readily 
  

   in 
  the 
  solution 
  upon 
  heating 
  and 
  crystallizes 
  in 
  slender 
  hex- 
  

   agonal 
  prisms 
  terminated 
  by 
  the 
  pyramid. 
  When 
  the 
  ratio 
  of 
  

   the 
  caesium 
  chloride 
  to 
  the 
  thallic 
  chloride 
  is 
  30 
  g. 
  to 
  50 
  g. 
  a 
  

   salt 
  is 
  obtained 
  which 
  crystallizes 
  in 
  hexagonal 
  plates. 
  Analy- 
  

   ses 
  of 
  the 
  plates 
  do 
  not 
  agree 
  very 
  closely 
  with 
  theory, 
  but 
  it 
  

   is 
  evident 
  that 
  they 
  are 
  the 
  same 
  as 
  the 
  prismstic 
  salt 
  with 
  

   another 
  crystalline 
  habit. 
  The 
  high 
  percentage 
  of 
  caesium 
  and 
  

   the 
  corresponding 
  low 
  percentage 
  of 
  thallium 
  is 
  probably 
  due 
  

   to 
  the 
  slight 
  inclusions 
  held 
  by 
  the 
  crystals, 
  which 
  could 
  be 
  

   seen 
  with 
  the 
  microscope. 
  This 
  salt 
  is 
  white, 
  permanent 
  in 
  

   the 
  air 
  and 
  recrystallizes 
  unchanged 
  from 
  water. 
  The 
  analyses 
  

   given 
  below 
  are 
  of 
  separate 
  crops 
  made 
  under 
  very 
  different 
  

   conditions. 
  

  

  Caesium. 
  Thallium. 
  Chlorine. 
  Water. 
  

  

  A 
  34-93 
  -65 
  

  

  B 
  ._. 
  35-09 
  35-64-35-51 
  28'09-27-99 
  

  

  C 
  28-06 
  -95 
  

  

  D 
  35-63 
  

  

  E 
  _ 
  35-03 
  35-69 
  28'06 
  

  

  F 
  (Plates) 
  . 
  . 
  . 
  36-64 
  33'85 
  2815 
  

  

  G 
  (Plates).-- 
  36-18 
  34'46 
  28-18 
  '61 
  

  

  Stic^^} 
  35 
  ' 
  42 
  36 
  ' 
  22 
  28 
  ' 
  36 
  

  

  The 
  water 
  found 
  in 
  these 
  analyses 
  was 
  probably 
  held 
  mechan- 
  

   ically 
  by 
  the 
  crystals. 
  

  

  The 
  prismatic 
  variety 
  of 
  this 
  salt 
  showed 
  only 
  the 
  forms 
  of 
  

   the 
  prism, 
  1010, 
  and 
  pyramid, 
  1011. 
  

  

  Axis 
  c 
  = 
  0-82566 
  0001^1011 
  = 
  43° 
  37' 
  50" 
  

  

  Measured. 
  Calculated. 
  

  

  p 
  *p, 
  1011^0111 
  *40° 
  21' 
  

  

  m^p, 
  1010^1011 
  46 
  2l£; 
  46° 
  22' 
  46° 
  22' 
  

  

  Sections 
  parallel 
  to 
  the 
  basal 
  plane 
  show 
  in 
  convergent 
  

   polarized 
  light 
  the 
  normal 
  uniaxial 
  interference 
  figure, 
  with 
  

   weak 
  negative 
  double 
  refraction. 
  The 
  crystals 
  served 
  very 
  

   well 
  as 
  60° 
  prisms 
  for 
  the 
  determination 
  of 
  the 
  indices 
  of 
  

   refraction 
  with 
  the 
  following 
  results 
  : 
  

  

  Red, 
  Li. 
  Yellow, 
  Na. 
  Green, 
  Tl. 
  

  

  od 
  — 
  ■ 
  1-772 
  1 
  784 
  1-792 
  

  

  e 
  = 
  1-762 
  1-774 
  1-786 
  

  

  3:1 
  Rubidium 
  Thallic 
  Bromide, 
  fib, 
  Tl 
  Br 
  6 
  . 
  H^O.— 
  This 
  

   salt 
  was 
  formed, 
  when 
  1*5 
  to 
  24 
  g. 
  of 
  thallic 
  bromide 
  were 
  

  

  