Trace Sciences International

Erbium Isotopes

Nominal Mass
Accurate Mass
% Natural Abundance
Chemical Form
Enrichment Available %

162 Er

161.928775 (4)

0.14 (1)

oxide

22 – 39+

164 Er

163.929198 (4)

1.61 (3)

oxide

62 – 82+

166 Er

165.930290 (4)

33.6 (35)

oxide

96 – 98+

167 Er

166.932046 (4)

22.95 (17)

oxide

94 – 96+

168 Er

167.932368 (4)

26.8 (26)

oxide

98+

170 Er

169.935461(4)

14.9 (27)

oxide

97 – 98+

Erbium has six stable isotopes. Er-168 has a well established application for the production of Er-169 which is used in form of citrate for the treatment of rheumatoid arthritis.