Isotopes of boron

Boron (₅B) naturally occurs as isotopes ¹⁰
B
and ¹¹
B
, the latter of which makes up about 80% of natural boron. There are 13 radioisotopes that have been discovered, with mass numbers from 7 to 21, all with short half-lives, the longest being that of ⁸
B
, with a half-life of only 771.9(9) ms and ¹²
B
with a half-life of 20.20(2) ms. All other isotopes have half-lives shorter than 17.35 ms. Those isotopes with mass below 10 decay into helium (via short-lived isotopes of beryllium for ⁷
B
and ⁹
B
) while those with mass above 11 mostly become carbon.