Living Reference Work Entry

Encyclopedia of Geochemistry

Part of the series Encyclopedia of Earth Sciences Series pp 1-6

Date: Latest Version

Boron Stable Isotopes

  • Gavin L. FosterAffiliated withOcean and Earth Science, National Oceanography Centre Southampton, University of Southampton Email author 
  • , Christophe LécuyerAffiliated withLaboratoire de Géologie de Lyon, LGL-TPE, CNRS UMR 5276, Université Claude Bernard Lyon 1 & Institut Universitaire de France Email author 
  • , Horst R. MarschallAffiliated withDepartment of Geology & Geophysics, Woods Hole Oceanographic InstitutionInstitut für Geowissenschaften, Goethe-Universität Frankfurt Email author 


Boron, a group 13 metalloid, has two natural occurring stable isotopes, 11B (11.00930536[45]) and 10B (10.01293695[41]), with relative abundances of 0.199(7) and 0.801(7), respectively, and hence occurs approximately in a 4:1 ratio (source of data: National Institute of Standards and Technology, http://​www.​nist.​gov/​pml/​data/​comp.​cfm). Numerous radioisotopes of boron also occur with masses from 7B to 17B, but their half-lives are all <1 s. As with other stable isotopic systems, natural isotope variation is described using delta notation, i.e., the per mil variation from the 11B/10B ratio of the synthetic boric acid international reference material NIST SRM-951 (atom%: 11B = 80.173 ± 0.013; 10B = 19.827 ± 0.013; Catanzaro et al., 1970). This can be described by the following equation: ...

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