Hydrogen fluoride and hydrogen chloride are highly acidic. It spontaneously chlorine and fluorine to form hydrogen chloride and hydrogen fluoride, respectively. The fluorine compounds decompose into products including fluoride ions. Examples include calcium, zinc, manganese, phosphate, fluoride and sodium compounds. Crystals of calcium sulfate or calcium fluoride are doped with dysprosium. Sodium fluoride and sodium chloride adopt the same structure. Potassium chloride converts to KF upon treatment with hydrogen fluoride. The solubility of halide salts increases from fluoride to iodide. Topical fluoride is used in toothpaste, mouthwash and fluoride varnish. Similarly, toothpaste typically contains a source of fluoride anions (e.g. sodium fluoride, sodium monofluorophosphate). Phosphate rocks contain high levels of fluoride. Other molecules like hydrogen fluoride, ammonia and methanol can also form hydrogen bonds. Currently, most beryllium is produced by reducing beryllium fluoride with magnesium. Examples include water, most alcohols, formic acid, hydrogen fluoride, and ammonia. Plants can be damaged by high fluoride or boron levels.