Period 3 element in 1810, who named it chlorine, from the Greek word χλωρος (chlōros), meaning "green-yellow." Chlorine is a component of various compounds, including table salt. It is the second most abundant halogen and 21st most abundant chemical element in Earth's crust. The great oxidizing potential of chlorine led it to its bleaching and disinfectant uses, as well as uses of an essential reagent in the chemical industry. As a common disinfectant, chlorine compounds are used in swimming pools to keep them clean and sanitary. In the upper atmosphere, chlorine-containing molecules such as chlorofluorocarbons have been implicated in ozone depletion. "Argon" (symbol
Pyromorphite chemical tests. They were formerly confused under the names green lead ore and brown lead ore ("German: Grünbleierz and Braunbleierz"). The phosphate was first distinguished chemically by M. H. Klaproth in 1784, and it was named pyromorphite by J. F. L. Hausmann in 1813. The name is derived from the Greek for "pyr" (fire) and "morfe" (form) due to its crystallization behavior after being melted. "Paecilomyces javanicus" is a mold collected from a lead-polluted soil that is able to form biominerals of pyromorphite. The color of the mineral is usually some bright shade of green, yellow or brown, and the