The phase, surface adsorption, and dispersion of iron catalysts impregnated on coal were characterized using Mossbauer spectroscopy. The magnetic relaxation behavior of the catalyst is similar to that obtained from binary ferrihydrite catalysts; the catalyst particles are aggregated rather than dispersed or "impregnated" on coal and the surface of the catalyst is chemisorbed with impurity anions. These impurity anions inhibit particle agglomeration, thus allowing the catalyst to maintain its surface area under reaction conditions.