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,
Nickel silver (Shadow model); these are far rarer than traditional lacquered brass saxophones. Student-level flutes and piccolos are also made of silver-plated nickel silver, although upper-level models are likely to use sterling silver. Nickel silver produes a bright and powerful sound quality; an additional benefit is that the metal is harder and has more corrosion resistance than brass. Because of its hardness, it is the most commonly used material for woodwind keys. Most clarinets, flutes, oboes and similar wind instruments have nickel silver keys, normally silver-plated. It is used to produce the tubes (called staples) onto which oboe reeds are tied. Many