Editing Boron (section)

===Isotopes===
{{Main|Isotopes of boron}}
Boron has two naturally occurring and stable [[isotope]]s, <sup>11</sup>B (80.1%) and <sup>10</sup>B (19.9%). The mass difference results in a wide range of δ<sup>11</sup>B values, which are defined as a fractional difference between the <sup>11</sup>B and <sup>10</sup>B and traditionally expressed in parts per thousand, in natural waters ranging from −16 to +59. There are 13 known isotopes of boron; the shortest-lived isotope is <sup>7</sup>B which decays through [[proton emission]] and [[alpha decay]] with a [[half-life]] of 3.5×10<sup>−22</sup> s. Isotopic fractionation of boron is controlled by the exchange reactions of the boron species B(OH)<sub>3</sub> and [[tetrahydroxyborate|[B(OH)<sub>4</sub>]<sup>−</sup>]]. Boron isotopes are also fractionated during mineral crystallization, during H<sub>2</sub>O phase changes in [[hydrothermal]] systems, and during [[hydrothermal alteration]] of [[rock (geology)|rock]]. The latter effect results in preferential removal of the [<sup>10</sup>B(OH)<sub>4</sub>]<sup>−</sup> [[ion]] onto clays. It results in solutions enriched in <sup>11</sup>B(OH)<sub>3</sub> and therefore may be responsible for the large <sup>11</sup>B enrichment in seawater relative to both [[ocean]]ic crust and [[continent]]al crust; this difference may act as an [[isotopic signature]].<ref>{{Cite journal| first = S.|last = Barth| title = Boron isotopic analysis of natural fresh and saline waters by negative thermal ionization mass spectrometry| journal = Chemical Geology| volume = 143|date = 1997|pages = 255–261|doi = 10.1016/S0009-2541(97)00107-1| issue = 3–4|bibcode = 1997ChGeo.143..255B}}</ref>

The exotic <sup>17</sup>B exhibits a [[nuclear halo]], i.e. its radius is appreciably larger than that predicted by the [[semi-empirical mass formula|liquid drop model]].<ref>{{Cite journal| title = Two-body and three-body halo nuclei| first = Z.|last = Liu|journal = Science China Physics, Mechanics & Astronomy| volume = 46| date= 2003| page = 441|doi = 10.1360/03yw0027| issue = 4| doi-broken-date = 3 May 2025|bibcode = 2003ScChG..46..441L| s2cid = 121922481}}</ref>

====NMR spectroscopy====
Both <sup>10</sup>B and <sup>11</sup>B possess [[nuclear spin]]. The nuclear spin of <sup>10</sup>B is 3 and that of <sup>11</sup>B is {{sfrac|3|2}}. These isotopes are, therefore, of use in [[nuclear magnetic resonance]] spectroscopy; and spectrometers specially adapted to detecting the boron-11 nuclei are available commercially. The <sup>10</sup>B and <sup>11</sup>B nuclei also cause splitting in the [[resonances]] of attached nuclei.<ref>{{cite web| title = Boron NMR| url = http://rmn.iqfr.csic.es/guide/eNMR/chem/B.html| access-date= 5 May 2009|publisher = BRUKER Biospin| archive-url = https://web.archive.org/web/20090502140944/http://rmn.iqfr.csic.es/guide/eNMR/chem/B.html <!--Added by H3llBot-->| archive-date = 2 May 2009}}</ref>