Overview of the materials of the ADAP code and their transitions. The accreted material is either MetSilWat (cold accretion) or MetSil (hot accretion where water vapour is lost in the accretion process). The code includes four material transitions: melting of water, desiccation of clay, melting of iron and melting of silicates. Liquid water is released both when ice is melted and when clays become unstable; the remaining water is transferred to oxidized metal MeO and clays.