Mercury

Mercury (chemical symbol Hg) is a chemical element. It is a metal, but the only metal that is liquid at normal room temperature. Its appearance is silvery and shiny, and it has a high density compared to other liquids, which is why other metals such as lead float on it.

The symbol Hg derives from the Latin name 'hydrargyrum', meaning 'liquid silver'. The name 'mercury' is connected to Roman mythology and the planet Mercury, stemming from the historical association between the metal and the planet in alchemy.

Physical and chemical properties

Mercury combines with other metals such as gold, tin and copper to form what is called an amalgam. This combination has long been used in extracting gold from ore and in dental fillings. Mercury does not mix with water, and on the surface of other liquids it forms large drops with high surface tension, which means when spilled it breaks into small spheres.

Mercury compounds are divided into two distinct types: inorganic compounds (such as mercury chloride and mercury sulfide) and organic compounds (such as methylmercury). The most common ore from which mercury is extracted is cinnabar (mercury sulfide), which has a dark red color.

Uses

Historically, mercury was used in thermometers, barometers, fluorescent lamps, and electrical switches. It was also used in factories producing chlorine and sodium hydroxide. Due to health hazards, many countries have now restricted its use, and electronic devices have been found as replacements.

Health and environmental effects

Mercury is a neurotoxin. Mercury vapor when inhaled affects the brain, kidneys and respiratory system. Methylmercury accumulates in the bodies of sea fish, particularly large predatory fish high in the food chain. Pregnant women and children are especially vulnerable to its effects on brain development. The Minamata Convention, an international agreement, is aimed at reducing mercury emissions to the environment.