Reed Relays and
Electronics India Limited
Manufacturer of Reed Switches, Reed Sensors and Reed-based products
Reed Relays and Electronics India Limited Incorporated in 1971


Mercury is a chemical element with the symbol Hg (Hydrargyrum in Latin) and atomic number 80. It is a heavy, silvery metal that is liquid at room temperature and atmospheric pressure and when ingested, is poisonous. This metal is banned by the RoHS directive 2011.

Mercury_(element) (Wikipedia)

Mercury, 80Hg
Pouring liquid mercury bionerd.jpg
Appearanceshiny, silvery liquid
Standard atomic weight Ar, std(Hg)200.592(3)
Mercury in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson


Atomic number (Z)80
Groupgroup 12
Periodperiod 6
Block  d-block
Electron configuration[Xe] 4f14 5d10 6s2
Electrons per shell2, 8, 18, 32, 18, 2
Physical properties
Phase at STPliquid
Melting point234.3210 K ​(−38.8290 °C, ​−37.8922 °F)
Boiling point629.88 K ​(356.73 °C, ​674.11 °F)
Density (near r.t.)13.534 g/cm3
Triple point234.3156 K, ​1.65×10−7 kPa
Critical point1750 K, 172.00 MPa
Heat of fusion2.29 kJ/mol
Heat of vaporization59.11 kJ/mol
Molar heat capacity27.983 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 315 350 393 449 523 629
Atomic properties
Oxidation states−2 , +1, +2 (a mildly basic oxide)
ElectronegativityPauling scale: 2.00
Ionization energies
  • 1st: 1007.1 kJ/mol
  • 2nd: 1810 kJ/mol
  • 3rd: 3300 kJ/mol
Atomic radiusempirical: 151 pm
Covalent radius132±5 pm
Van der Waals radius155 pm
Other properties
Natural occurrenceprimordial
Crystal structurerhombohedral
Rhombohedral crystal structure for mercury
Speed of soundliquid: 1451.4 m/s (at 20 °C)
Thermal expansion60.4 µm/(m⋅K) (at 25 °C)
Thermal conductivity8.30 W/(m⋅K)
Electrical resistivity961 nΩ⋅m (at 25 °C)
Magnetic orderingdiamagnetic
Molar magnetic susceptibility−33.44×10−6 cm3/mol (293 K)
CAS Number7439-97-6
DiscoveryAncient Egyptians (before 1500 BCE)
Main isotopes of mercury
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
194Hg syn 444 y ε 194Au
195Hg syn 9.9 h ε 195Au
196Hg 0.15% stable
197Hg syn 64.14 h ε 197Au
198Hg 10.04% stable
199Hg 16.94% stable
200Hg 23.14% stable
201Hg 13.17% stable
202Hg 29.74% stable
203Hg syn 46.612 d β 203Tl
204Hg 6.82% stable
Category Category: Mercury (element)
| references

Mercury is a chemical element with the symbol Hg and atomic number 80. It is commonly known as quicksilver and was formerly named hydrargyrum (/hˈdrɑːrərəm/ hy-DRAR-jər-əm). A heavy, silvery d-block element, mercury is the only metallic element that is liquid at standard conditions for temperature and pressure; the only other element that is liquid under these conditions is the halogen bromine, though metals such as caesium, gallium, and rubidium melt just above room temperature.

Mercury occurs in deposits throughout the world mostly as cinnabar (mercuric sulfide). The red pigment vermilion is obtained by grinding natural cinnabar or synthetic mercuric sulfide.

Mercury is used in thermometers, barometers, manometers, sphygmomanometers, float valves, mercury switches, mercury relays, fluorescent lamps and other devices, though concerns about the element's toxicity have led to mercury thermometers and sphygmomanometers being largely phased out in clinical environments in favor of alternatives such as alcohol- or galinstan-filled glass thermometers and thermistor- or infrared-based electronic instruments. Likewise, mechanical pressure gauges and electronic strain gauge sensors have replaced mercury sphygmomanometers.

Mercury remains in use in scientific research applications and in amalgam for dental restoration in some locales. It is also used in fluorescent lighting. 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.

Mercury poisoning can result from exposure to water-soluble forms of mercury (such as mercuric chloride or methylmercury), by inhalation of mercury vapor, or by ingesting any form of mercury.

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