Copper(I) oxide or cuprous oxide (Cu2O) is an oxide of copper. It is insoluble in water and organic solvents. Copper(I) oxide dissolves in concentrated ammonia solution to form the colorless complex[Cu(NH3)2]+, which easily oxidizes in air to the blue[Cu(NH3)4(H2O)2]2+. It dissolves in hydrochloric acid to form HCuCl2 (a complex of CuCl), while dilute sulfuric acid and nitric acid produce copper(II) sulfate and copper(II) nitrate, respectively. Copper(I) oxide is the mineral cuprite in some red-colored rocks. When exposed to oxygen, copper will naturally oxidize to copper(I) oxide, but this takes extended periods. The artificial formation is usually accomplished at high temperatures or high oxygen pressure. With further heating, copper(I) oxide will form copper(II) oxide. Formation of copper(I) oxide is the basis of Fehling's test and Benedict's test for reducing sugars which reduce an alkaline solution of a copper(II) salt and give a precipitate of Cu2O. Cuprous oxide forms on silver-plated copper parts exposed to moisture when the silver layer is porous or damaged; this corrosion is known as red plague. Copper(I) oxide was the first substance known to behave as a semiconductor. Rectifier diodes based on this material were used industrially as early as 1924, long before silicon became the standard. Copper(I) oxide shows four well-understood series of excitons with resonance widths in the range of new. The associated polaritons are also well understood; their group velocity turns out to be very low, almost down to the speed of sound. That means light moves almost as slowly as sound in this medium. This results in high polariton densities, and effects like Bose-Einstein condensation, the dynamical Stark effect, and proportions have been demonstrated. If you are looking for high quality, high purity, and cost-effective Copper oxide, or if you require the latest price, please email contact mis-asia.