Provides links and references to additional resources related to mercury. Provides information on methods for sampling the difference forms of mercury. Mercury hazards are addressed in specific OSHA standards for general industry, maritime, and construction. Protecting Workers from Mercury Exposure While Crushing and Recycling Fluorescent Bulbs.


Gaseous mercury is added to cold cathode argon-filled lamps to increase the ionization and electrical conductivity. An argon-filled lamp without mercury will have dull spots and will fail to light correctly. Lighting containing mercury can be bombarded/oven pumped only once.

A trip to Mercury requires more rocket fuel than that required to escape the Solar System completely. A proposed alternative approach would use a solar sail to attain a Mercury-synchronous orbit around the Sun. This means that Schiaparelli’s and Antoniadi’s maps were not “wrong”.


Larger albedo features correspond to higher reflectivity plains. Mercury has dorsa (also called “wrinkle-ridges”), Moon-like highlands, montes , planitiae , rupes , and valles . Mercury is the smallest planet in the solar system, and it is also the planet closest to the Sun, making it the most difficult of the planets to see with the unaided eye. Because its rising or setting is always within about two hours of the Sun’s, Mercury is never observable when the sky is fully dark.

This method bypasses the limitation of twilight observing when the ecliptic is located at a low elevation (e.g. on autumn evenings). Mercury is more often and easily visible from the Southern Hemisphere than from the Northern. This is because Mercury’s maximum western elongation occurs only during early autumn in the Southern Hemisphere, whereas its greatest eastern elongation happens only during late winter in the Southern Hemisphere.

They form tetrahedral complexes with other ligands but the halides adopt linear coordination geometry, somewhat like Ag+ does. Best known is mercury chloride, an easily sublimating white solid. HgCl2 forms coordination complexes that are typically tetrahedral, e.g. Native mercury with cinnabar, Socrates mine, Sonoma County, California.


One distinctive feature of Mercury’s surface is the presence of numerous narrow ridges, extending up to several hundred kilometers in length. It is thought that these were formed as Mercury’s core and mantle cooled and contracted at a time when the crust had already solidified. Mercury appears to have a solid silicate crust and mantle overlying a solid, iron sulfide outer core layer, a deeper liquid core layer, and a solid inner core.

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The origin of the ice on What is Mercury is not yet known, but the two most likely sources are from outgassing of water from the planet’s interior or deposition by impacts of comets. Smooth plains are widespread flat areas that fill depressions of various sizes and bear a strong resemblance to the lunar maria. Unlike lunar maria, the smooth plains of Mercury have the same albedo as the older inter-crater plains. Despite a lack of unequivocally volcanic characteristics, the localisation and rounded, lobate shape of these plains strongly support volcanic origins. All the smooth plains of Mercury formed significantly later than the Caloris basin, as evidenced by appreciably smaller crater densities than on the Caloris ejecta blanket. Craters on Mercury range in diameter from small bowl-shaped cavities to multi-ringed impact basins hundreds of kilometers across.

Mercury’s surface appears heavily cratered and is similar in appearance to the Moon’s, indicating that it has been geologically inactive for billions of years. The polar regions are constantly below 180 K (−93 °C; −136 °F). Like Venus, Mercury orbits the Sun within Earth’s orbit as an inferior planet, and its apparent distance from the Sun as viewed from Earth never exceeds 28°.

  • The floors of deep craters at the poles are never exposed to direct sunlight, and temperatures there remain below 102 K, far lower than the global average.
  • The earliest known recorded observations of Mercury are from the MUL.APIN tablets.
  • Because it’s the closest planet to the sun, it goes around the Sun in just 88 Earth days.
  • Thus, industries that release high concentrations of mercury into the environment agreed to install maximum achievable control technologies .
  • Such liquid-mirror telescopes are cheaper than conventional large mirror telescopes by up to a factor of 100, but the mirror cannot be tilted and always points straight up.
  • Search the HHE database for more information on chemical topics.

Although ice was not the only possible cause of these reflective regions, astronomers think it was the most likely. The planet’s mantle is chemically heterogeneous, suggesting the planet went through a magma ocean phase early in its history. Crystallization of minerals and convective overturn resulted in layered, chemically heterogeneous crust with large-scale variations in chemical composition observed on the surface.

Chlorine is produced from sodium chloride using electrolysis to separate the metallic sodium from the chlorine gas. By-products of any such chloralkali process are hydrogen and sodium hydroxide , which is commonly called caustic soda or lye. Many of the industrial mercury releases of the 20th century came from this process, although modern plants claimed to be safe in this regard. After about 1985, all new chloralkali production facilities that were built in the United States used membrane cell or diaphragm cell technologies to produce chlorine.

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The purest of these was gold, and mercury was called for in attempts at the transmutation of base metals into gold, which was the goal of many alchemists. Mercury remains in use in scientific research applications and in amalgam for dental restoration in some locales. Electricity passed through mercury vapor in a fluorescent lamp produces short-wave ultraviolet light, which then causes the phosphor in the tube to fluoresce, making visible light. Pluto was considered a planet from its discovery in 1930 to 2006, but after that it has been reclassified as a dwarf planet. Pluto is also smaller than Mercury, but was thought to be larger until 1976. Encounters, the origin of Mercury’s magnetic field remained the subject of several competing theories.


The crust is low in iron but high in sulfur, resulting from the stronger early chemically reducing conditions than is found in the other terrestrial planets. The surface is dominated by iron-poor pyroxene and olivine, as represented by enstatite and forsterite, respectively, along with sodium-rich plagioclase and minerals of mixed magnesium, calcium, and iron-sulfide. The less reflective regions of the crust are high in carbon, most likely in the form of graphite.

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Artists, like followers of Roman religion themselves, freely borrowed the attributes of Hermes and portrayed Mercury also wearing winged sandals or a winged cap and carrying a caduceus . Mercury, Latin Mercurius, in Roman religion, god of shopkeepers and merchants, travelers and transporters of goods, and thieves and tricksters. He is commonly identified with the Greek Hermes, the fleet-footed messenger of the gods. Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.

This proximity to the Sun means the planet can only be seen near the western horizon after sunset or the eastern horizon before sunrise, usually in twilight. At this time, it may appear as a bright star-like object, but is more difficult to observe than Venus. From Earth, the planet telescopically displays the complete range of phases, similar to Venus and the Moon, which recurs over its synodic period of approximately 116 days. The synodic proximity of Mercury to Earth makes Mercury most of the time Earth’s closest planet, despite Venus at times approaching Earth closer than any other planet can. Mercury’s fleet management consulting services help organizations improve the management, performance (reliability, safety, sustainability.), and costs of their vehicle and equipment fleets. The smallest planet in our solar system has a big presence in our collective imagination.

Protocols call for physically merging smaller droplets on hard surfaces, combining them into a single larger pool for easier removal with an eyedropper, or for gently pushing the spill into a disposable container. Vacuum cleaners and brooms cause greater dispersal of the mercury and should not be used. Afterwards, fine sulfur, zinc, or some other powder that readily forms an amalgam with mercury at ordinary temperatures is sprinkled over the area before itself being collected and properly disposed of. Cleaning porous surfaces and clothing is not effective at removing all traces of mercury and it is therefore advised to discard these kinds of items should they be exposed to a mercury spill. Mercury chloride has been used in traditional medicine as a diuretic, topical disinfectant, and laxative.

Much of Mercury’s surface rock could have been vaporized at such temperatures, forming an atmosphere of “rock vapor” that could have been carried away by the solar wind. A third hypothesis proposes that the solar nebula caused drag on the particles from which Mercury was accreting, which meant that lighter particles were lost from the accreting material and not gathered by Mercury. Mercury’s core has a higher iron content than that of any other major planet in the Solar System, and several theories have been proposed to explain this. The most widely accepted theory is that Mercury originally had a metal–silicate ratio similar to common chondrite meteorites, thought to be typical of the Solar System’s rocky matter, and a mass approximately 2.25 times its current mass.

The planet’s density is the second highest in the Solar System at 5.427 g/cm3, only slightly less than Earth’s density of 5.515 g/cm3. If the effect of gravitational compression were to be factored out from both planets, the materials of which Mercury is made would be denser than those of Earth, with an uncompressed density of 5.3 g/cm3 versus Earth’s 4.4 g/cm3. Mercury’s density can be used to infer details of its inner structure. Although Earth’s high density results appreciably from gravitational compression, particularly at the core, Mercury is much smaller and its inner regions are not as compressed.

Nonetheless, the brightest appearance of Mercury is an essentially impossible time for practical observation, because of the extreme proximity of the Sun. Mercury is best observed at the first and last quarter, although they are phases of lesser brightness. The first and last quarter phases occur at greatest elongation east and west of the Sun, respectively. At both of these times Mercury’s separation from the Sun ranges anywhere from 17.9° at perihelion to 27.8° at aphelion. At greatest western elongation, Mercury rises at its earliest before sunrise, and at greatest eastern elongation, it sets at its latest after sunset. Mercury can, like several other planets and the brightest stars, be seen during a total solar eclipse.

Cinnabar sometimes alters to native mercury in the oxidized zone of mercury deposits. Beginning in 1558, with the invention of the patio process to extract silver from ore using mercury, mercury became an essential resource in the economy of Spain and its American colonies. Mercury was used to extract silver from the lucrative mines in New Spain and Peru. Initially, the Spanish Crown’s mines in Almadén in Southern Spain supplied all the mercury for the colonies. Mercury deposits were discovered in the New World, and more than 100,000 tons of mercury were mined from the region of Huancavelica, Peru, over the course of three centuries following the discovery of deposits there in 1563. The patio process and later pan amalgamation process continued to create great demand for mercury to treat silver ores until the late 19th century.