Terbium: Tb2O3 Electrolysed in Fused Lithium-Terbium Fluoride at 900 °C on a Graphite Cathode (Endoh, Kunitomo and Sugimura, US 5,258,103)

Terbium oxide as sold contains some four-valent terbium, and then the electrolysis gives nothing. Heated in argon it turns to white Tb2O3, which dissolves in a molten lithium-terbium fluoride bath and is reduced to terbium metal on a graphite cathode. Result: 140 g of terbium metal from 172 g of Tb2O3. Source: H. Endoh, H. Kunitomo and N. Sugimura, US 5,258,103 (1993), Example 2. Molten fluorides are toxic; work at 900 °C under argon. Picture drawn by Youblob.