Rhodium is separated from the residue by treatment with molten sodium bisulfate. It can also be made by mixing potassium permanganate with sodium bisulfate and hydrogen peroxide. Rhodium can be separated from the residue by treatment with molten sodium bisulfate. Various existing preparations include the hydrochloride, dihydrochloride, sulfate, bisulfate and gluconate. Mercallite, the mineralogical form of potassium bisulfate, occurs very rarely. Sodium bisulfate is used primarily to lower pH. Misenite is another more complex form of potassium bisulfate with the formula KH(SO). Sulfur trioxide can be prepared in the laboratory by the two-stage pyrolysis of sodium bisulfate. The liquid sodium bisulfate is sprayed and cooled so that it forms a solid bead. With potassium bisulfate mucic acid forms 3-hydroxy-2-pyrone by dehydration and decarboxylation. This is because sodium bisulfate catalyses deamination of unmethylated cytosine to uracil. For example, is the sulfate anion, and , the hydrogensulfate (or bisulfate) anion. Potassium bisulfate is commonly used to prepare potassium bitartrate for winemaking. Sodium bisulfate is effective at mutating G/C rich genomic sequences. Sodium bisulfate is considered generally recognized as safe (GRAS) by the FDA.