Europium: Oxide Reduced with Lanthanum Turnings at 1200 °C in High Vacuum, Metal Distilled and Melted Down (Ames Laboratory, 1956)

Europium boils far more easily than lanthanum. Heated with lanthanum turnings in a high vacuum, europium oxide gives up its oxygen to the lanthanum and the europium distils off, to be melted down into a tantalum cup under argon. Result: europium metal, over 90 % yield; it melts below 900 °C and reacts quickly with air and water. Source: Ames Laboratory, Semi-annual summary research report in chemistry ISC-757 (1956), section 3.1.3. Work at 1200 °C in high vacuum; europium reacts with water. Picture drawn by Youblob.