The reaction between iron(III) oxide and barium carbonate in vacuo

The reaction between iron(III) oxide and barium carbonate was studied in vacuo, thus enabling the collection of the carbon dioxide evolved. The extent of reaction was calculated from the amount of carbon dioxide and from the X-ray analysis of the solid products.When a highly reactive iron oxide was used, reaction was detected at a temperature ca. 100° below that with a sintered iron oxide. Only three compounds of barium, iron, and oxygen were found, namely BaO, Fe2O3, 2BaO, Fe2O3, and BaO, 6Fe2O3.The ferrite BaO, Fe2O3 results from the direct reaction of barium carbonate with iron oxide at low temperatures. The reaction of BaO, Fe2O3 with Fe2O3 to give BaO, 6Fe2O3 requires higher temperatures. The observations appeared to be explicable in terms of Tammann temperatures.