﻿Frequency 
  and 
  Molecular 
  Number. 
  457 
  

  

  Group 
  VI. 
  

  

  In 
  the 
  sixth 
  group 
  of 
  the 
  Periodic 
  Table 
  only 
  a 
  dozen 
  

   compounds 
  need 
  be 
  considered. 
  Several 
  of 
  these 
  are 
  oxides, 
  

   and 
  it 
  is 
  noticeable, 
  both 
  here 
  and 
  elsewhere, 
  that 
  these 
  in 
  

   general 
  necessitate 
  large 
  values 
  for 
  vx. 
  

  

  It 
  is 
  interesting 
  to 
  find 
  that 
  salts 
  of 
  the 
  heaviest 
  metal, 
  

   uranium, 
  appear 
  to 
  conform 
  to 
  the 
  same 
  rule 
  as 
  salts 
  of 
  the 
  

   lightest 
  metal, 
  lithium. 
  Thus 
  lithium 
  fluoride, 
  with 
  molecular 
  

   number 
  12, 
  has 
  for 
  ~Nv 
  the 
  value 
  5^X 
  21'0 
  x 
  10 
  12 
  , 
  uranium 
  

   hexafluoride, 
  with 
  molecular 
  number 
  146, 
  has 
  the 
  value 
  

   5x21-0xl0 
  12 
  ; 
  lithium 
  iodide 
  (N 
  = 
  56) 
  gives 
  Ni/ 
  = 
  6x20'8 
  

   X 
  10 
  12 
  , 
  whilst 
  uranium 
  tetra-iodide, 
  with 
  the 
  large 
  molecular 
  

   number 
  of 
  304, 
  gives 
  Nv 
  = 
  9 
  X 
  20«7 
  x 
  10 
  12 
  . 
  

  

  Group 
  VI. 
  

   Sulphur 
  Compounds 
  (N 
  = 
  16). 
  

  

  Name. 
  Formula. 
  N. 
  vXlO~ 
  12 
  . 
  N^xlO 
  -12 
  . 
  

  

  Sulphur 
  

  

  trioxide 
  /3 
  (S0 
  3 
  ) 
  2 
  80 
  0816 
  3 
  X21-7 
  

  

  Sulphuric 
  

  

  acidpyro 
  ... 
  H 
  2 
  S 
  2 
  7 
  90 
  0890 
  4x20*0 
  

  

  Selenium 
  Compounds 
  (N 
  = 
  34). 
  

  

  Selenium 
  

  

  dioxide 
  Se0 
  2 
  50 
  2-473 
  6 
  x20*6 
  

  

  oxychloride 
  SeOCl 
  2 
  76 
  0-984 
  3^x21*4 
  

  

  Selenic 
  

   acid 
  H 
  2 
  Se0 
  4 
  68 
  1-269 
  4 
  x216 
  

  

  Tellurium 
  Compound 
  (N 
  = 
  52). 
  

   Tellurium 
  

   tetrabromide 
  TeBr 
  4 
  192 
  0*792 
  7^X20*3 
  

  

  Chromium 
  Compounds 
  (N 
  = 
  24). 
  

   Chromium 
  

  

  trioxide 
  Cr0 
  3 
  48 
  2-030 
  4±x21*7 
  

  

  Chromic 
  

  

  oxide 
  Cr 
  2 
  3 
  72 
  3*876 
  13x21-5 
  

  

  Chromous 
  

  

  fluoride 
  CrF 
  2 
  42 
  4*300 
  8|x21-2 
  

  

  Molybdenum 
  Compound 
  (N 
  = 
  42). 
  

   Molybdenum 
  

   trioxide 
  M0O3 
  66 
  2-576 
  8 
  x21*2 
  

  

  Uranium 
  Compounds 
  (N=92). 
  

   Uranium 
  

  

  fluoride 
  hexa- 
  UF 
  6 
  146 
  0*719 
  5 
  X210 
  

  

  iodidetetra- 
  UI^ 
  304 
  0*614 
  9 
  X20*7 
  

  

  oxide 
  di- 
  U0 
  2 
  108 
  3*182 
  16 
  X21-5 
  

  

  