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Hydrogen Peroxide–urea
Hydrogen peroxide–urea (also called Hyperol, artizone, urea hydrogen peroxide, and UHP) is a white crystalline solid chemical compound composed of equimolar amounts of hydrogen peroxide and urea. It contains solid and water-free hydrogen peroxide, which offers a higher stability and better controllability than liquid hydrogen peroxide when used as an oxidizing agent. Often called carbamide peroxide in dentistry, it is used as a source of hydrogen peroxide when dissolved in water for bleaching, disinfection and oxidation. Production For the preparation of the complex, urea is dissolved in 30% hydrogen peroxide (molar ratio 2:3) at temperatures below 60 °C. upon cooling this solution, hydrogen peroxide–urea precipitates out in the form of small platelets. Akin to water of crystallization, hydrogen peroxide cocrystallizes with urea with the stoichiometry of 1:1. The compound is simply produced (on a scale of several hundred tonnes a year) by the dissolution of urea in exc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystalline Solid
A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macroscopic single crystals are usually identifiable by their geometrical shape, consisting of flat faces with specific, characteristic orientations. The scientific study of crystals and crystal formation is known as crystallography. The process of crystal formation via mechanisms of crystal growth is called crystallization or solidification. The word ''crystal'' derives from the Ancient Greek word (), meaning both "ice" and " rock crystal", from (), "icy cold, frost". Examples of large crystals include snowflakes, diamonds, and table salt. Most inorganic solids are not crystals but polycrystals, i.e. many microscopic crystals fused together into a single solid. Polycrystals include most metals, rocks, ceramics, and ice. A third category o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
