Isotope fractionation become enriched in the liquid phase while the lighter isotopes (O and H) tend toward the vapor phase. Isotope fractionation Isotope fractionation describes processes that affect the relative abundance of isotopes, often used in isotope geochemistry. Normally, the focus is on stable isotopes of the same element. Isotopic fractionation in the natural environment can be measured by isotope analysis, using isotope-ratio mass spectrometry, to separate different element isotopes on the basis of their mass-to-charge ratio, an important tool to understand natural systems. For example, in biochemistry processes cause a fluctuation in the amount of isotopes of carbon ratios incorporated into
Standard atomic weight publishes "abridged" values (up to five digits per number only), and for the twelve interval values, "conventional" values (single number values). Symbol "A" is a relative atomic mass, for example from a specific sample. To be specific, the standard atomic weight can be noted as , where (E) is the element symbol. The abridged atomic weight, also published by CIAAW, is derived from the standard atomic weight reducing the numbers to five digits (five significant figures). The name does not say 'rounded'. Interval borders are rounded "downwards" for the first (lowmost) border, and "upwards" for the "upward" (upmost) border. This