684 The Philippine Journal of Science 1921 
Schmidlin “" in 1908 observed that solutions of the colorless 
solid are at first colorless but that they acquire color after 
standing a few seconds. He was able to show that the colorless 
triphenlymethy] is only partially converted into the colored modi- 
fication and that even in solution the two modifications exist in 
equilibrium with each other. He also showed that the colored 
form was more reactive. 
Schlenck * in 1910 gave a new impetus to the trivalent carbon 
theory by preparing analogues of triphenylmethy] containing di- 
phenyl groups. The determination of the molecular weights of 
these compounds showed some of them to exist largely in the 
monomolecular form. The colored modifications of triarylme- 
thyls are monomolecular, some even in the solid state, as, for 
instance, tribiphenylmethyl. 
Piceard,"* Schmidlin,‘* and Schlenk and Mair,* using differ- 
ent methods, came to the conclusion that all solutions of hex- 
aphenylethane contain monomolecular triphenylmethyl, the 
amount of this in benzol at 80° C. reaching 25 to 30 per cent 
of the whole amount of the hydrocarbon dissolved. 
PRESENT THEORY 
The various theories as to the structure of the triarylmethyls 
cited above tend in the right direction but have been befogged 
by our old affinity unit conception of valence. The epoch-making 
articles by Langmuir ** on the arrangement of electrons and 
atoms in the molecule have made possible an entirely new con- 
ception of the mechanism of organic reactions which leads to 
a consistent explanation of the constitution and the ichemical 
and physical properties of the triarylmethyls. The coexistence 
of two or more modifications of a triarylmethyl as shown, for 
example, by molecular weight determinations, can now be ex- 
plained more clearly than by the indefinite term tautomerism. 
In the following discussion the Lewis-Langmuir theory of va- 
lence will be applied to this problem along the lines suggested 
by Perkins,‘* whose nomenclature will, in general, be followed. 
“ Schmidlin, J., Ber. deutsch. chem. Ges. 41 (1908) 2471. 
® Schlenck, N.; Weickel, T. U.; Herzenstein, A., Ann. d. Chem. 372 
(1910) 1; Ber. deutsch. chem. Ges. 43 (1910) 1753. 
: * Piccard, J., Ann. d. Chem. 381 (1911) 347. 
“Schmidlin, J., Ber. deutsch. chem. Ges. 45 (1912) 3180. 
* Schlenk, W. u. Mair, L., Ann. d. Chem. 394 (1912) 179. 
* Langmuir, I., Journ. Am. Chem. Soc. 41 (1919) 868, 1543; 42 (1920) 
.274. 
* Perkins, G. A., Philip. Journ. Sci. 19 (1921) 825. 
