ytterbium oxide

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A colorless hygroscopic compound, Yb₂O₃, used in certain alloys, ceramics, and optical glasses.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun inorganic chemistry Any oxide of ytterbium, but especially the colourless solid Yb2O3 (itterbia or ytterbia)