When people talk about “active manganese dioxide”, they usually mean that the content was specially treated to increase its oxidation activity. Regular MNO₂ can be quite inactive, especially when wet or crystalline. The active manganese dioxide, however, has a more porous and dry powder with several reactive sites on its surface. It is ideal for oxidizing alleil alcohol manganese dioxide . It works well with alile and benzel alcohol, converting them into this aldehyde or ketone.