Other inorganic fluorides prepared from hydrofluoric acid include sodium fluoride and uranium hexafluoride. Fluoride salts and hydrofluoric acid are the main fluorides of industrial value. Metal fluorides with more fluorine atoms are particularly reactive. Many of the elements that form volatile high-valence fluorides will also form volatile high-valence chlorides. The two other binary fluorides of xenon do not form such stable adducts with fluoride. Studies have found that mouthwashes containing potassium salts and fluorides can reduce dentine hypersensitivity. The product, chloryl fluoride, is one of the five known chlorine oxide fluorides. Metathesis reactions employing alkali metal fluorides are the simplest. OF reacts with many metals to yield oxides and fluorides. Other important inorganic fluorides include those of cobalt, nickel, and ammonium. Few inorganic fluorides are soluble in water without undergoing significant hydrolysis. The nonmetal binary fluorides are volatile compounds. Other metal fluorides are produced using HF, including uranium hexafluoride. However, sulfur fluorides with high valences, such as sulfur hexafluoride, are stable and well-known. Certain selenium fluorides, such as selenium difluoride, have been produced in small amounts.