Mercury (sometimes called quick silver) is the only metal that is liquid at room temperature. It is also one of only two elements that are liquid at room temperature. The other liquid element is the halogen bromine. Named after the god and planet Mercury, its symbol (Hg) reflects its liquid nature as the Greek word “hydrargyrum” translates as liquid silver.
Man has known of this element for thousands of years. Archeologists have found mercury in Egyptian tombs dating to 1500 BCE. The ancient Chinese and Hindus were also aware of this fascinating liquid metal.
Its atomic number, 80, puts mercury in period 6, group 12 and the d-block of elements in the periodic table. It has an atomic weight of 200.59 and a density of 13.5336 grams per cubic centimeter. Its ionization energy is 10.438 eV and it has two oxidation states +2 and +1.
Although occasionally found as a free element, most commercially available mercury comes from the mineral ore cinnabar. Spain and Italy are the main suppliers of the metal with the largest deposits of this mineral.
With a melting point of minus 38.83°C (234.32 K, minus 37.89°F) and a boiling point of 356.73°C (629.88 K, 674.11°F) mercury is frequently used in thermometers. Other uses of the pure metal include in barometers and silent tilt activated electrical switches.
Mercury forms amalgams with most metals. In particular, it forms an amalgam with gold. This ability allows it usage in extraction of gold. Unfortunately, mercury is an environmental toxin and pollution of streams at gold mining sites has led to damage whole river ecosystems in some parts of the world. Amalgams with silver form dental fillings, while extended life batteries contain amalgams of zinc or cadmium.
Mercury vapor is dangers at levels in excess 0.1 milligrams per cubic meter. Because of this, rooms in which mercury is handled must have good ventilation. Poisoning also occurs by the absorption of mercury through the digestive tract or through the skin. Mercury poisoning results in a number of symptoms including neurological disorders and infertility, fatalities also occur. Toxic organic compounds containing mercury, such as methyl mercury, in industrial pollutants causes damage to aquatic ecosystems.
Mercury vapor combines with the noble gases xenon, argon, neon and krypton. This makes mercury one of the few elements able to combine with these elements. When the gases are subjected to an electrical discharge, these compounds form. Van der Waals’ forces act on the resulting atoms preventing them from disassociating.