On Molecule Symmetry, Latent Heat, and Entropy

This paper suggested correlating the entropy with the geometric symmetry of the molecular orbits instead of the atomic mass distribution in a molecule. Employing the NIST thermodynamic parameters of substances at saturation, linear regressions of exothermic heat over T give ε_exo=B-(3+2A)/2 RT. B is the molar heat of liquefication, which equals the latent heat (∆H_v^Φ) at the boiling point. A reflects the molecule's symmetry; the more symmetric the molecular orbits, the smaller A. For example, the symmetry of inert gas atoms gives the operation number n = 1 in the theoretical frame of the geometric symmetry of atomic mass distribution. However, three p orbits give n = 7; correspondingly, A values of Ne, Ar, Kr, and Xe are 2.5518, 2.9104, 2.9140, and 2.9178. Similarly, a tetrahedron of C sp3 gives n = 8, CH4: A=2.9519. Hence, assuming that (3+2A)/2 R is the lost entropy, (n-2A)/2 R may be regarded as the residual in liquid. According to the above suggestion, CO is more symmetric than CO2. Moreover, the similarity in A between ethylene and ethane, propylene and propane, etc., implies that the C-C π bond should be rotatable rather than rigid. Helium-4 superfluid finds an increase in entropy as T decreases from 3.5 to 0.8 K. Clausius-Clapeyron equation was derived from ε_exo.