Thulium(III) oxide

Thulium(III) oxide is a pale green crystalline compound, with the formula Tm2O3. It was first isolated in 1879, from an impure sample of erbia, by Swedish chemist Per Teodor Cleve, who named it thulia.

Synthesis
Thulium(III) oxide has been made in the laboratory using various methods. One method involves burning thulium metal or its various salts in air.

Thulium(III) oxide can be made using a hydrothermal method where thulium(III) acetate is mixed with an ammonia solution, which causes thulium(III) oxide to precipitate as a white solid.