Samarium oxide, deposition

Eecent work by L. M. Dermis2 and his co-workers has shown that electrolysis may be of considerable value in effecting a complete or partial separation of the oxides of the rare earth metals. Prom a neutral solution of the nitrates of neodymium, praseodymium, lanthanum, and samarium, nearly all the lanthanum is deposited as hydroxide in the last fractions discharged on the cathode. The hydroxides are deposited fractionally in order of their basicity, and the deposition is not dependent upon the... 

The final step, vaporization of calcium, does not work for metals with high vapor pressure, as the metal itself would vaporize with the calcium. Instead the oxide is reduced with metallic lanthanum, which has a very low vapor pressure. Lanthanum oxide and a melt of the actual RE metal are formed. The reduction reaction occurs in a tantalum container. The reduced RE metals e.g. samarium, are vaporized and deposit on the walls of the tantalum container. This method is used for [boiling point (°C) in parenthesis] Sm (1794), Eu (1529), Tm (1950), Yb (1196). 

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