Pure Red Mercury , 99.999% Mercury

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