479.    CHAUDRON, G., AND FORESTIER, H.  [Decomposition of Ferrous Oxide.  Anomalies of Dilatation Correlative to Its Instability.]  Compt. Rend., vol. 178, 1924, pp. 2173-2176; Chem. Abs., vol. 18, 1924, p. 3306.

                 Object was to study the velocities of 2 reactions involved in the equilibrium 4 FEO=Fe₃O₄+Fe.  FeO was prepared at 800°-900° and cooled rapidly to avoid decomposition.  It was then heated in a vacuum for 24 hr. at constant temperature and analyzed by treating with dilute CuSO₄ for 12 hr.  Titration with KMnO₄ gave the weight of Fe that entered the solution.  The fraction of the FeO transformed in 24 hr. was plotted against the temperature.  At 300° free Fe could be determined.  The fraction transformed then increased to 80% at 480°, passing through a maximum there and falling to 0% at 570°.  At 592°, 24% of FeO and at 600°, 51% of FeO were formed in 24 hr. from a sample originally containing 20% of FeO.  At 445° the velocity of the reaction is expressed by dx/dt=k(100-x)⁴.  When change in volume is plotted against temperature, anomalies are observed corresponding to the chemical changes.

                 CHAUKAVIN, M. K.  See abs. 2754.