A method for completely reducing an inorganic halide to obtain a non-halogen inorganic substance and/or hydride thereof and preferably anhydrous hydrogen halide fluid using inorganic halide substances, such as sulfur hexafluoride, nitrogen trifluoride, tungsten hexafluoride, uranium hexafluoride and others by reduction with a reducing agent at a proper temperature. The reducing agents may be molecular hydrogen, inorganic hydrides and inorganic metallic elements; molecular hydrogen is preferable, but in certain instances the inorganic hydrides are used, as well as inorganic metallic elements such as calcium and magnesium.