19, 6 
Cole: Dissociation of Hexaphenylethane 
687 
reunite in such a manner that C (tf) is attached to C (i), form- 
ing the compound: 
Two neutral molecules of B can probably also unite and re- 
arrange to give E. 
The above explanation leads us to the conclusion that hex- 
aphenylethane can exist in the modifications A, B, C, D, and E. 
This is essentially the same conclusion that Gomberg arrived 
at, except that colorless triphenylmethyl can exist, according 
to the present theory, only in the form of a negative ion, and 
that, in the positive ion, one of the para carbon atoms has two 
unsatisfied affinity units. As for trivalent carbon, the form B 
contains a para carbon atom in a truly trivalent condition, name- 
ly, with one unsatisfied affinity unit. The positive ion exists 
only in combination with a solvent molecule. The negative ion 
contains a carbon atom (the central atom) in the satisfied but 
tricovalent condition which is found in many organo-metallic 
compounds, and is particularly stable when three pairs of elec- 
trons are strongly drawn away from a carbon kernel (as in the 
case of metallic acetylene derivatives). 
Having explained the existence of the various types of hex- 
aphenylethane let us examine their chemical and physical proper- 
ties in the light of the octet theory. 
Color . — Hexaphenylethane is colorless in the solid state; it 
has colored and colorless modifications in solution. We would 
expect the compound B, the positive ion D and the compound 
E to be colored, owing to the presence of the quinoid group. 
On the other hand, the negative ion C and hexaphenylethane 
A should be colorless. It should be possible to demonstrate 
experimentally that the positive ion is the colored ion and the 
negative ion colorless by electrolysis of a solution of hexaphenyl- 
ethane in a dissociating solvent. 
Piccard 18 by applying Beer’s colored solution law shows that 
a solution of hexaphenylethane in ether undergoes dissociation 
from R f ,C 2 to R 3 C as dilution increases. If the solution is 
caused to crystallize, only the polymer R 0 C 2 is deposited be- 
PHYSICAL PROPERTIES 
18 Piccard, J., Ann. d. Chem. 381 (1911) 347. 
