Group 12 element have zinc in its active site. In 1817, cadmium was discovered in Germany as an impurity in zinc carbonate minerals (calamine) by Friedrich Stromeyer and Karl Samuel Leberecht Hermann. It was named after the Latin "cadmia" for "calamine", a cadmium-bearing mixture of minerals, which was in turn named after the Greek mythological character, Κάδμος Cadmus, the founder of Thebes. Stromeyer eventually isolated cadmium metal by roasting and reduction of the sulfide. In 1927, the International Conference on Weights and Measures redefined the meter in terms of a red cadmium spectral line (1 m = 1,553,164.13 wavelengths). This definition has since
Group 11 element silver-plated copper wiring are found in some special applications. Copper occurs in its native form in Chile, China, Mexico, Russia and the USA. Various natural ores of copper are: copper pyrites (CuFeS), cuprite or ruby copper (CuO), copper glance (CuS), malachite, (Cu(OH)CuCO), and azurite (Cu(OH)2CuCO). Copper pyrite is the principal ore, and yields nearly 76% of the world production of copper. Silver is found in native form, as an alloy with gold (electrum), and in ores containing sulfur, arsenic, antimony or chlorine. Ores include argentite (AgS), chlorargyrite (AgCl) which includes horn silver, and pyrargyrite (AgSbS). Silver is extracted using the