440 FOOTE AND mohIvEr: ionization 



in ordei to occur at all must immediately follow the first step, 

 it is a very improbable condition in low voltage arcs. Ioniza- 

 tion resulting in the production of a positively charged mercuric 

 chloride ion is considered later. 



It would appear that a very probable type of ionization of 

 mercuric chloride results in the production of a positively charged 

 mercurous chloride ion and a negatively charged chlorine ion. 



The ionization of mercurous chloride may result in the fol- 

 lowing immediate conditions: 



(i) A positively charged molecule (HgCl) + 

 (2) A positively charged mercury atom and a negatively 

 charged chlorine atom (Hg)+ + (Cl)~ 



We would expect to find both types of ionization present. 

 That the first type may occur is reasonable since positively 

 charged mercurous chloride ions may be produced in the ioniza- 

 tion of mercuric chloride. The second type of ionization is in 

 direct analogy to that of the alkali halides. 



The thermochemical relations may be written for the above 

 modes of ionization. 



Let J'ugci represent ionization of type (Hg)+ + (Cl)~ 

 J Hgci represent ionization of type (HgCl) "^ 

 /'Hgchi^epresent ionization of type (Hg)"^"*" + 2(01)" 

 / Hgch represent ionization of type (HgCl) + + (CI) ~ 

 J'ug represent ionization of type (Hg)++ x 



J Hg represent ionization of type (Hg) + 

 [ ] denotes soHd phase, ( ) gaseous phase, and no sign, liquid 

 phase. 



L = latent heat of fusion per mol. 



Accordingly we have for the ionization of (HgCl2) into (Hg)++ 

 and 2(C1)~: 



[HgCl2] + Qngch = Hg -f (CI2) 

 Hg - LHg = [Hg] 



++ 



[Hg] + 5Hg^ = (Hg) 



(Hg) + /'Hg = (Hg) 



(CI2) + 2Dci = 2 (CI) 



2 (CI) - 2£ci = 2(C1)- 



(HgCl2) - Sngcb = [HgCl2] 



