quicksilver

Quicksilver is the common name for the chemical element mercury (Hg), a dense, silvery liquid metal that is the only metal to be liquid at room temperature. Mercury has atomic number 80 and occurs naturally in the Earth’s crust mainly as the mineral cinnabar (mercuric sulfide, HgS). Its liquid state and high density have long made it useful in various scientific and industrial applications.

The term quicksilver derives from the Old English quick meaning alive or moving, reflecting mercury’s fluid, highly mobile nature. The element is also known by the Latin name hydrargyrum, from hydro- (water) and argyros (silver), which yields its chemical symbol Hg.

Physical properties include a melting point of −38.83 °C and a boiling point of 356.73 °C, making it one of the few metals liquid at ordinary conditions. Mercury is dense (about 13.5 g/cm3) and forms amalgams with many metals. It is a relatively poor conductor of heat compared with solid metals and exhibits low chemical reactivity at ambient temperatures, though it oxidizes at higher temperatures and can form toxic compounds.

Occurrence and production: Mercury is chiefly obtained from cinnabar ore through roasting to release elemental mercury, followed by purification by distillation.

Uses: Historically and still today, mercury has been used in thermometers, barometers, electrical switches, fluorescent lamps, and dental amalgams. It also participates in some gold extraction methods and various scientific instruments, though many applications have declined due to toxicity concerns.

Safety and environmental aspects: Mercury and its compounds are highly toxic, particularly as inhaled vapor or in organic forms such as methylmercury. Exposure can affect the nervous system and kidneys, and environmental contamination poses long-term health risks. Safe handling, containment, and proper disposal are essential.