a process of chemical vapor deposition particularly useful as support materials are metal oxides which will not react with the hematite or with the chemicals to be catalyzed such as titanium dioxide or zirconium dioxide the preferred support material however is alumina particularly u03b1 alumina which is a finer and more active form of alumina chemical vapor deposition may be conducted either in a conventional process or in a pack process in both processes a ferric halide gas is formed by the reaction of a hydrogen halide with a source of iron such as hematite while any hydrogen halide such as hydrogen bromide or hydrogen iodide could be used hydrogen chloride is preferred as it is easier to work with if another hydrogen halide gas is used reaction temperatures must be adjusted accordingly the ferric halide gas and water vapor are the reaction products at the higher temperatures at the lower temperatures the reaction is reversed and u03b1 fe 2 o 3 is produced by the water vapor hydrolysis of the ferric halide vapor the overall reaction is in the conventional chemical vapor deposition process the source of iron is placed upstream to the support material and the hydrogen halide gas flows over the iron source forming the corresponding ferric halide gas the ferric halide gas reacts with water vapor to deposit the hematite on the support material this process may be.