Alloy of mixed rare earth metals. Prepd by electrolysis of fused rare earth chlorides. Obtained from the lanthanide ore, bastnaesite. A typical composition is 48-50% cerium, 32-34% lanthanum, 13-14% neodymium, 4-5% praseodymium and 1.5% other rare earth metals. Average mol wt is 140. Uses in organic synthesis: M.-I. Lannou et al., Tetrahedron 59, 10551 (2003).