Solar induced chemical reactions can be divided into thermochemical or photochemical. Compilers of thermochemical databases may contain some additional thermodynamic functions. Whatever gas remains is then made into pyrolysis oil by thermochemical processes. This reaction is similar to thermochemical sulfate reduction in geochemistry. The higher temperature enables the production of hydrogen by thermochemical processes. The iron oxide cycle is a series of thermochemical processes used to produce hydrogen. More than 352 thermochemical cycles have been described for water splitting or thermolysis. The sulfur-iodine cycle (S-I cycle) is a series of thermochemical processes used to produce hydrogen. In particular, see the thermochemical sulfur-iodine cycle. This method is advantageous as it can be benchmarked against experimentally-determined thermochemical values. The ionic model holds up well in thermochemical calculations. This thermochemical work required extremely precise measurements. More than 200 thermochemical cycles can be used for water splitting. Using the thermochemical equation of variables as above, one gets the following example. There are two general conditions under which thermochemical measurements are made.