To increase the available data oil systems containing supercritical water and inorganic compounds, all experimental setup was designed to investigate the solubilities of inorganic compounds Ill supercritical water, In this work, three alkali chloride salts (LiCl, NaCl, KCl) and three alkali nitrate salts (LiNO(3), NaNO(3), KNO(3)) were investigated in the range from (653 to 693) K and from (18 to 23.5) MPa. The experimental results were correlated with a model based on the phase equilibrium between the inorganic compound and supercritical water. When available, the experimental data were extended with data available ill the open literature. The experimental results and parameters obtained by this model were compared with each other and evaluated under consideration of the physical aspects of the inorganic compounds. In addition to the Main purpose of the experiments, side reactions like decomposition of nitrate and changes in pH were observed and discussed in this work. The presented data are the first coherent Study of the Solubility of six common inorganic compounds in one setup and with one method.