Über die isomeren Dikobaltoctacarbonyle. II. Die Enthalpie und Entropiedifferenz der beiden isomeren Dikobaltoctacarbonyle

It is known that dicobalt‐octacarbonyl consists in solution of an equilibrium mixture of two isomeres, one (I) with, the other (11) without carbonyl bridges. From the temperature dependence of the absorption intensities in the infrared spectrum of the two isomers the enthalpy difference is found to be −1.30 kcal/mole. Isomer II is less stable then isomer I. The entropy difference is +5 cal/mole deg. A pentane solution contains at room temperature 43% of I and 57% of 11, at −104°C 84% of I and 16% of II.