Barium permanganate heptoxide. Barium permanganate Barium permanganate is a chemical compound, with the formula Ba(MnO). Barium permanganate may be produced by disproportionation of barium manganate in a mildly acidic solution, or by oxidation of barium manganate with strong oxidants. Preparations relying on aqueous reactions of barium manganate are extremely slow process due to the low solubility of the manganate. Permanganic acid can be prepared by the reaction of dilute sulfuric acid with a solution barium permanganate, the insoluble barium sulfate byproduct being removed by filtering: The sulfuric acid used must be dilute; reactions of permanganates with concentrated sulfuric acid yield the anhydride,
Pewter Pewter Pewter () is a malleable metal alloy. It is traditionally composed of 85–99% tin, mixed with copper, antimony, bismuth, and sometimes silver or lead, although the use of lead is less common today. Copper and antimony act as hardeners while lead is more common in the lower grades of pewter, which have a bluish tint. Pewter has a low melting point, around , depending on the exact mixture of metals. The word "pewter" is probably a variation of the word "spelter", a term for zinc alloys (originally a colloquial name for zinc). Pewter was first used around the beginning