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10.3A: Protium and Deuterium

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    34052
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    Properties of hydrogen

    The difference of mass between isotopes of most elements is only a small fraction of the total mass and so this has very little effect on their properties, this is not the case for hydrogen. Consider chlorine with Z=17, there are 2 stable isotopes 35Cl (75.77%) and 37Cl (24.23%). The increase is therefore 2 in 35 or less than 6%. Deuterium and tritium are about double and triple the mass of protium and show significant physical and chemical differences particularly with regard to those properties related to mass, e.g. rate of diffusion, density, etc.

    Some physical properties of the hydrogen isotopes.
    isotope MP /K BP /K ΔHdiss /kJmol-1 Interatomic Distance /pm
    H2 13.99 20.27 435.99 74.14
    D2 18.73 23.67 443.4 74.14
    T2 20.62 25.04 446.9 74.14
    Differences between H2O and D2O
    Property H2O D2O
    Melting point /K 273.15 276.97
    Boiling point /K 373.15 374.5
    Temperature of maximum density /K 277 284.2
    Maximum density /g cm3 0.99995 1.1053
    Relative permittivity (at 298 K) 78.39 78.06
    Kw (at 298 K) 1 *1014 2 * 1015
    Symmetric stretch, ν1 /cm-1
    (gaseous molecule)
    3657 2671

    10.3A: Protium and Deuterium is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts.

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