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.