mercurio

Mercurio is the chemical element with the symbol Hg and the atomic number 80. It is a dense, silvery-grey metal that is liquid at room temperature, making it the only common metal found in a liquid state under ordinary conditions. Mercury occurs naturally in the mineral cinnabar (mercury sulfide) and in smaller amounts in other minerals and rocks. Commercial production is mainly achieved by extracting mercury from cinnabar through roasting to release mercury vapor, which is then condensed.

Mercury has a high density, about 13.5 g/cm3, and a relatively low melting point of −38.83 °C and a boiling point of 356.73 °C. It forms amalgams with many metals, notably gold, silver, zinc, and tin. In compounds, mercury commonly adopts the +2 oxidation state, though various other oxidation states exist in different chemical contexts. Elemental mercury is relatively unreactive but can form a range of compounds, including oxides and sulfides, under appropriate conditions.

Historically significant for its use in thermometers, barometers, electrical switches, and laboratory equipment, mercury has also been employed in dental amalgams and some industrial processes. Many of these applications have declined due to health, safety, and environmental concerns. Mercury and many of its compounds are toxic, capable of affecting the nervous, digestive, and immune systems, and can bioaccumulate in ecosystems, particularly in aquatic food chains. Major contemporary sources of mercury emissions include coal-fired power plants, artisanal and small-scale gold mining, and improper disposal of mercury-containing products.

Mercury is also the name of the planet closest to the Sun and a Roman deity in other contexts; in scientific writing about the element, the term mercurio refers specifically to the chemical substance described here.