Despite of the great interest in accretion disks around supermassive black holes there are still numerous controversies about their structure and their physical properties. Therefore we have calculated the structure of such disks for a wide range of parameters. For the viscosity we use a standard α-description with the main component of the stress tensor trϕ proportional to the gas pressure. The disk structure depends sensitively on material properties such as opacities and specific heats. In our calculations we have used an equation of state and mean opacities taking into account a list of the most important ionization processes as well as the radiation contributions to thermodynamic quantities.