Praseodymium sesquioxide, Pr₂O₃

Praseodymium sesquioxide, or praseodymia, Pr₂O₃, is obtained by reducing the dioxide at a red heat in a stream of hydrogen. It is a yellowish-green powder of density 6.88 (or 7.07) at 15°. When heated in the air it absorbs oxygen and becomes brown in colour.