i9, 6 Cole: Dissociation of Hexaphenylethane 689 
Here we have, then, a satisfactory explanation of the oxidation 
of hexaphenylethane without the supposition of the compound 
existing in the form of the radicle triphenylmethyl. That is, the 
reaction is to a large extent of the direct-addition rather than 
the dissociation-addition type. 
The oxidation of the colored compound E proceeds in a some- 
what analogous manner, the chemically negative oxygen molecule 
attaching itself to either carbon atom C(f) or C (2) ; the break 
occurs and the peroxide is formed. 
Similarly oxygen adds to the central carbon of compound B. 
The product contains an uneven number of electrons, which 
probably causes a three-electron bond to be formed between the 
oxygen atoms. In this case the shift of electrons in the oxygen 
molecule is toward the outer atom, which thus becomes very 
active in attacking the positive open spaces in the shell of the 
central carbon atom of another molecule of B, thus forming the 
same peroxide as above-mentioned. 
Addition of hydrogen. — Molecular hydrogen does not react 
with hexaphenylethane. Zinc dust and acetic acid, however, 
cause the addition of hydrogen, which probably occurs as follows : 
Zinc like any positive metal furnishes free electrons, which cause 
the formation of negative ions (formula C) at its surface. These 
negative ions rapidly combine with hydrogen ions furnished by 
the acid, and triphenylmethane is formed. 
Addition of halogen. — Chlorine and bromine form both sub- 
stitution and addition products ; iodine forms only addition prod- 
ucts with hexaphenylethane. The halogen molecule contains a 
number of unshared electrons, one or more of which during a 
thermal impact enter an exposed positive space in the distorted 
shell of the central carbon atom in compound B. By rearrange- 
ment to the benzoid form one of these electrons is accommodated 
in the shell. Any others that may enter are repulsed and one un- 
shared electron in the carbon atom shell joins the newly arrived 
halogen electron to form a shared pair between the carbon and 
halogen atoms. The excess of one electron causes the outer 
halogen atom to dissociate as a neutral atom, which is very active 
in substituting or adding to a second molecule of compound B. 
Addition of xylene. — Wieland and Muller 22 found that, on 
boiling hexaphenylethane with o- or p-xylene, dimethyltetra- 
phenylmethane is formed: 
(C 6 H 5 ) 6 C 2 + C 6 H 4 (CH 3 )2 - (C6H 5 ) 3 C.C 6 H s (CH 3 )2 ■+ (C 6 H 5 ) 3 CH. 
22 Wieland, H. u. Muller, C., Ann. d. Chem. 401 (1913) 238. 
