The objective of the present investigation was to determine the structural properties of the solid oxidation products of carbon blacks by the use of x-ray diffraction techniques in an attempt to gain information on the location and manner in which oxygen is combined with carbon in carbon blacks. Representative samples of carbon blacks prepared by channel, gas furnace, and oil furnace processes were oxidized by several different methods: (1) gaseous oxygen at 240-360° c. (2) 30% hydrogen peroxide in water (3) potassium chlorate dissolved in concentrated nitric and sulfuric acids and (4) 50% solution of concentrated nitric acid and water. The resulting solid oxidation products were the materials used in this study.