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Mercury is a chemical element; it has symbol Hg and atomic number 80. It is also known as quicksilver and was formerly named hydrargyrum (/ h aɪ ˈ d r ɑːr dʒ ər ə m / hy-DRAR-jər-əm) from the Greek words hydor ' water ' and argyros ' silver ', from which its chemical symbol is derived. [9]
There are seven stable isotopes of mercury (80 Hg) with 202 Hg being the most abundant (29.86%). The longest-lived radioisotopes are 194 Hg with a half-life of 444 years, and 203 Hg with a half-life of 46.612 days. Most of the remaining 40 radioisotopes have half-lives that are less than a day.
Inch of mercury (inHg and ″Hg) is a non-SI unit of measurement for pressure. It is used for barometric pressure in weather reports , refrigeration and aviation in the United States . It is the pressure exerted by a column of mercury 1 inch (25.4 mm) in height at the standard acceleration of gravity .
The best known polycation of mercury is Hg 2+ 2, in which mercury has a formal oxidation state of +1. The Hg 2+ 2 ion was perhaps the first metal-metal bonded species confirmed. The presence of the Hg 2+ 2 ion in solution was shown by Ogg in 1898. [7] In 1900, Baker showed the presence of HgCl dimers in the vapour phase. [8] The presence of Hg 2+
However, mercury can easily be reduced to the +1 oxidation state; usually, as in the ion Hg 2+ 2, two mercury(I) ions come together to form a metal-metal bond and a diamagnetic species. [24] Cadmium can also form species such as [Cd 2 Cl 6] 4− in which the metal's oxidation state is +1. Just as with mercury, the formation of a metal-metal ...
Mercury regulation in the United States limit the maximum concentrations of mercury (Hg) that is permitted in air, water, soil, food and drugs. The regulations are promulgated by agencies such as the Environmental Protection Agency (EPA) and Food and Drug Administration (FDA), as well as a variety of state and local authorities.
Mercury barometer. A millimetre of mercury is a manometric unit of pressure, formerly defined as the extra pressure generated by a column of mercury one millimetre high, and currently defined as exactly 133.322 387 415 pascals [1] or approximately 133.322 pascals. [2] It is denoted mmHg [3] or mm Hg. [4] [2]
Sodium amalgam is a by-product of chlorine made by mercury cell electrolysis. In this cell, brine (concentrated sodium chloride solution) is electrolysed between a liquid mercury cathode and a titanium or graphite anode. Chlorine is formed at the anode, while sodium formed at the cathode dissolves into the mercury, making sodium amalgam.