“…Thus, by electrolytic reduction at a mercury cathode in alkaline acetate solutions containing potassium citrate and potassium carbonate, McCoy (5,6) prepared europium, ytterbium, and samarium amalgams in yields decreasing in this order. By this method, europium was readily removed from rare earth mixtures (6) and ytterbium was extracted with somewhat less efficiency (7). While McCoy was unable to obtain amalgams of the other rare earth elements by this procedure, he did obtain europium, ytterbium, and samarium amalgams by treating acetate solutions containing citrate and potassium carbonate with potassium amalgam (5,6).…”