Electron Theory of Chemistry to Solids. 



753 



six atoms in NH 4 C1 had a separate cell the volume of 

 each would be 5*8. This is small compared with that 

 of the cells in any of the chlorides of the alkali meials ; so 

 that NH 4 C1 would have an abnormally small compressibility 

 compared with any of these salts. Though no deter- 

 minations of the compressibility of NH 4 C1 have been 

 published, there seems nothing to indicate that its com- 

 pressibility is abnormally small ; if it is not, then ammonium, 

 NH 4 , must behave like a single atom in NH 4 C1. 



Stability of chains of atoms. 



The possibility of atoms being linked together in long 

 chains is interesting from the point of view of organic 

 chemistry. We shall consider the case of a chain when the 

 electrons are arranged like a line of cubical boxes placed 

 end to end (fig. 5) ; the positively charged atoms are at the 

 centres of the cubes. The chain is supposed to be of infinite 

 length. 



Kff. 5. 









p' 



Q' 





R' 



\ 





\ 



\ 



P 



\. 



\ 









p" 1 





ft 





r" 1 



\ 



\ 





\ 



\ 





Consider first the forces exerted by the electrons on each 

 other. 



The force in the direction P"P on an electron P, due to 

 the other electrons, will, if a is the side of one of the 

 cubes, be 



tf\ 1 + 2 \W 2 + W 2+ lW" + lW 2+ ''\l + n 2 ) S ! 2 + "•)_}' 



due to the electrons in the line Q"B/'S"; and 



1 



a 2 \ 2 3/2 + l \ 5-3/2 + 6 3/2 + ^Z/2 + 



due to those along the line QUIT'S 7 

 The first part is equal to 



'(2+n>yi'' 



+ 



■■■)} 



the second to 



2-03 - 2 i 

 a 2 



1-01 



Phil. Mag. S. 6. Vol. 43. No. 256. April 1922. 



3C 



