Assertion: erbium | /r/HasAspect | six stable isotopes
Facets:
Source sentences:
text: Erbium has six stable isotopes but only Er-168 appears to have a well established application.
text: Er has six stable isotopes – 162
text: Erbium has six stable isotopes but only Er-168 appears to have a well established application.
text: It is bright, soft metal and has six stable isotopes: 162Er, 164Er, 166Er, 167Er, 168Er and 170Er.