regarded as Compounds of the First Order. 451 



and neon. He writes (loc. cit.) " the lithium atoms are 

 electric doublets and attract one another .... the electro- 

 static forces involved are just like those holding together 

 a crystal of sodium chloride. The positively charged lithium 

 kernels and the electrons will therefore arrange them- 

 selves in space in a continuous lattice, in a manner quite 

 analogous to that of the sodium and chlorine atoms in 

 sodium chloride." In neon, on the other hand, " the stray 

 field of force " of the atoms is very slight, and its great 

 volatility and inertness are indicative of its non-polar 

 character (see Trans. Chem. Soc, cxv. p. 282 (1919)). 



Polymerization of the elements. 



Just as the molecules of a polar compound have a tendency 

 to combine (see Trans. Chem. Soc. cxi. p. 253 (1917)), so 

 the atoms of a polar element attract one another. This 

 attraction may result in the formation of a space lattice 

 structure as seen above with lithium, or it may lead to the 

 formation of definite polymerides as in the cases of sulphur 

 and phosphorus. 



Attention may be directed to carbon which polymerizes in 

 chains according to Langmuir (J. Amer. Chem. Soc. xli. 

 p. 869 (1919)). Writing carbon as a compound C*E 4 , the 

 chain polvmeride may be represented by (1), which may be 

 compared with the formula (2) for polymerized ferric 

 cyanide, recentlv suggested by the author (Trans. Chem. 

 Soc. cxvii. p. 1028 (1920)). 



E E E * 



E E E > 



CN CN cn » 



->FeCNFeCNFeCN..-> etc. 



CN CN CN > 



(2) 



Co-ordination compounds of the elements. 



(1) Co-ordination compounds with a complex anion. — 

 When potassium and chlorine react, the chlorine atom 

 -completes its octet of electrons by taking the valency 

 electron from the potassium atom, according to the equation: 



K*E + 01%=K*[C1*E 8 .] (Note K*[C1*E 8 ] = K'Cl'O 



This equation may be compared with that representing the 

 reaction between potassium chloride and platinic chloride, 

 in which the platinum atom completes its octahedron of 



2 H 2 



