Molecular Symmetry and Related Properties

Abstract

The molecular rotational symmetry number, [sgrave], is defined and evaluated for a wide range of rigid organic compounds. Molecular symmetry is an important determinant of a variety of properties of crystalline substances. It is shown that the entropy of melting, ΔS_m, is related to symmetry by ΔS_m = 13.5–R In[sgrave]. Since molecular symmetry plays an important role in the determination of the entropy of melting it is also important in determining vapor pressure and ideal solubility, both of which depend upon entropy of melting.

Key Words:

• entropy of melting
• prediction
• estimation