Abstract
A normal coordinate analysis of the planar vibrations of some substituted ethylenes is carried out. Thirteen compounds are studied, including mono‐substituted and 1:1‐ and cis‐ and trans−1:2‐disubstituted ethylenes. Various solutions for the CH bending force constants are obtained and correlated. Some attempt is made to study the range of allowed solutions, and to examine the coupling of the different coordinates in the potential function.