Boron-10 abundance in nature

Abstract

THE most reliable values for the isotopic abundance of boron-10 in naturally occurring minerals have been derived from mass spectrometer measurements. Results quoted by different workers, however, range from 18.4 to 19.9 per cent boron-10, and it is not difficult to find possible causes for the variation. Most of the measurements have been made with boron trifluoride, which is a difficult compound to handle in a mass spectrometer, since memory effects and interference from impurities can give very erratic and incorrect results ; even when there are no errors of this kind, it is still possible for results to be biased by mass discriminations in the mass spectrometer, and no reported attempts have been made to standardize the results in any way. Insufficient care when preparing samples from the natural minerals could also cause errors arising from discrimination with respect to one isotope. The possibility of variation of the abundance of boron-10 in Nature has been investigated by Parwel et al.1, who examined a large number of minerals and found only a slight difference for boron obtained from sea water. © 1958 Nature Publishing Group.