Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; a freshly exposed surface has a reddish-orange color. It is used as a conductor of heat and electricity, a building material, and a constituent of various metal alloys. The metal and its alloys have been used for thousands of years. In the Roman era, copper was principally mined on Cyprus, hence the origin of the name of the metal as сyprium , later shortened to сuprum. Its compounds are commonly... encountered as copper salts, which often impart blue or green colors to minerals such as turquoise and have been widely used historically as pigments. Architectural structures built with copper corrode to give green verdigris . Decorative art prominently features copper, both by itself and as part of pigments. Copper ions are water-soluble, where they function at low concentration as bacteriostatic substances, fungicides, and wood preservatives.
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