Abnormalities in Vibrational Potential Constants

Abstract

A summary is presented of potential constants for =C= valence‐angle bending in a number of linear or quasilinear molecules. It is pointed out that these constants can vary over a wide range, with certain molecules having abnormally low values. One such low value in C₃O₂ helps to explain the infrared spectrum of that molecule. A very low value in C₃, obtained from spectroscopic measurements, is found to conflict with thermodynamic data.