Mercury compounds

Mercury,  ₈₀Hg

General properties
Pronunciation	/ˈmɜːrkjəri/ MER-kyə-ree
Appearance	silvery
Standard atomic weight (Ar, std)	7002200592000000000♠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 Cd ↑ Hg ↓ Cn gold ← mercury → thallium
Atomic number (Z)	80
Group, period	group 12, period 6
Block	d-block
Element category	post-transition metal, alternatively considered a transition metal
Electron configuration	[Xe] 4f14 5d10 6s2
Electrons per shell	2, 8, 18, 32, 18, 2
Physical properties
Phase (at STP)	liquid
Melting point	234.3210 K ​(−38.8290 °C, ​−37.8922 °F)
Boiling point	629.88 K ​(356.73 °C, ​674.11 °F)
Density (near r.t.)	13.534 g/cm3
Triple point	234.3156 K, ​1.65×10−7 kPa
Critical point	1750 K, 172.00 MPa
Heat of fusion	2.29 kJ/mol
Heat of vaporization	59.11 kJ/mol
Molar heat capacity	27.983 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 (mercuric), 1 (mercurous), −2 ​(a mildly basic oxide)
Electronegativity	Pauling scale: 2.00
Ionization energies	1st: 1007.1 kJ/mol 2nd: 1810 kJ/mol 3rd: 3300 kJ/mol
Atomic radius	empirical: 151 pm
Covalent radius	132±5 pm
Van der Waals radius	155 pm
Spectral lines
Miscellanea
Crystal structure	​rhombohedral
Speed of sound	liquid: 1451.4 m/s (at 20 °C)
Thermal expansion	60.4 µm/(m·K) (at 25 °C)
Thermal conductivity	8.30 W/(m·K)
Electrical resistivity	961 nΩ·m (at 25 °C)
Magnetic ordering	diamagnetic
Magnetic susceptibility	−33.44·10−6 cm3/mol (293 K)
CAS Number	7439-97-6
History
Discovery	Ancient Chinese and Indians (before 2000 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
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Spectral lines

Mercury is a chemical element with symbol Hg and atomic number 80. It is commonly known as quicksilver and was formerly named hydrargyrum (/haɪˈdrɑːrdʒərəm/). 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 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 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.