Chapter 9 - Chlorine

Abstract

Variations in the Cl isotope compositions of natural samples were first measured in 1982. It was shown by Aston that Cl consists of two different isotopes with masses 35 and 37. In later years, the Cl isotope ratio was determined quite often but because in nature the differences in Cl isotope ratios are small, no measurable variations were found. Variations in Cl isotope ratios were found in chemical experiments. Two samples of formation water had relatively large (although non-significant) deviations from the standard (-0.7 and -0.8‰), but they were not considered to be significantly different relative to the analytical precision.