19, 6 Perkins: Chlorine Dioxide and Compounds 737 
borrowing unions. Usually it is convenient to express such a 
union with a separate sign «, as already noted, to avoid con- 
fusion and show more graphically the valence relations. The 
equivalent sign *—~, however, is used in formula V. This 
formula shows two chlorate ions in the only position in which 
they would react smoothly with each other. The case of ClO, 
is practically identical. 
O~ O 
l 
es + 
O =F ee ee ea a 
E | 
) Oo 
V 
If the above explanation is correct, Cl,0, and Cl,O, are un- 
stable due to the inability of bi- or tricovalent chlorine to unite 
with bicovalent oxygen. ClO,, which contains no bicovalent oxy- 
gen, is therefore formed in reactions from which we might ex- 
pect Cl,0O, or Cl,0,. We may suppose that ClO, contains a 
three-electron bond without denying the strong general tendency 
toward sharing in pairs. In this particular case it seems that 
the pair-sharing tendency does not have an opportunity to mani- 
fest itself. The reasons against any disposition of the odd elec- 
tron other than in one of the bonds have already been given. 
Therefore, it seems highly probable that when an elec- 
tron is removed from one of the oxygen atoms in the ion 
os ae ( OxClaO- i forming the neu- 
tralmolecule, : 0 : Gl : O . ( OxCl—-O-— ), 
the vacancy caused in the oxygen shell is immediately filled by a 
closer approach to the chlorine shell in such a manner that one 
more electron is shared by the two atoms: 
ee . 
OO 2 Oe Ct Oreo J: 
Lewis’s notation is here used, the writer’s, which will be fur- 
ther explained in the succeeding section, being given in paren- 
thesis. It is to be noted’ that the union last mentioned causes 
