3433.    TRAUTZ, M., AND BADSTÜBNER, W.  [Vapor Pressure and Heat of Vaporization of Iron Pentacarbonyl.]  Ztschr. Elektrochem., vol. 35, 1929, pp. 799-802; Chem. Abs., vol. 24, 1930, p. 3690.

        Vapor pressure of Fe(CO)₅ was measured 47.56°-104.26°, by means of the apparatus of Trautz, Baisch, and Dechend.  Calculations of the heat of vaporization, by the Clausius-Clapeyron equation, showed that it gradually decreased from 9.65 kcal. at 23.78° to 8.79 kcal. at 98.98°.  From the pressures at 0° and 104.2°, and a value of 9.38 kcal. is obtained -- a value much higher than that of Dewar and Jones (Proc. Roy. Soc., vol. 76, A. 1905, pp. 558-577).  The lower values corresponding with the higher temperatures are attributed to the presence of Fe₂(CO)₉ dissolved in Fe(CO)₅, reducing its vapor pressure and raising its boiling points.