The structure and properties of graphite oxide depend on the particular synthesis method and degree of oxidation.[1][2] It typically preserves the layer structure of the parent graphite, but the layers are buckled and the interlayer spacing is about two times larger (~0.7 nm) than that of graphite. Strictly speaking "oxide" is an incorrect but historically established name. Besides epoxide groups (bridging oxygen atoms), other functional groups found experimentally are:[11] carbonyl (C=O), hydroxyl (-OH), phenol and for graphite oxides prepared using sulphuric acid (e.g. Hummers method) some impurity of sulphur is often found, for example in a form of organosulfate groups.[3][18][19][20][21][22] The detailed structure is still not understood due to the strong disorder and irregular packing of the layers.