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    Mercury

    IsotopeAtomic mass (Da)Isotopic abundance (amount fraction)
    196Hg 195.965 83(2)0.0015(1)
    198Hg 197.966 769(3)0.1004(3)
    199Hg 198.968 281(3)0.1694(12)
    200Hg 199.968 327(3)0.2314(9)
    201Hg 200.970 303(5)0.1317(9)
    202Hg 201.970 643(5)0.2974(13)
    204Hg 203.973 494(3) 0.0682(4)

    In 1961, the Commission recommended Ar(Hg) = 200.59(3) based on the chemical determinations. Published measurements of the isotopic composition of mercury agree remarkably well, giving Ar(Hg) values in the range 200.58 to 200.60. In 1989, new measurements of Hg isotope abundances led the Commission to reduce the uncertainty in the standard atomic weight or mercury. In 2011, new mass-spectrometric measurements led to Ar(Hg) = 200.592(3).

    SOURCE  Atomic weights of the elements: Review 2000 by John R de Laeter et al. Pure Appl. Chem. 2003 (75) 683-800
    © IUPAC 2003

    CIAAW

    Mercury
    Ar(Hg) = 200.592(3) since 2011

    The name derives from the Roman god Mercury, the nimble messenger of the gods, because the ancients used that name for the element known from prehistoric times. The symbol Hg derives from the Greek hydrargyrum for "liquid silver" or "quick silver".

    Isotopic reference materials of mercury.