METATHESIS ROUTES TO LANTHANIDE PNICTIDES

Reaction of Na3As or Na3Sb with anhydrous LnCl3 (Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tb, Yb) at 500-900-degrees-C in sealed Pyrex or quartz ampoules produces crystalline lanthanide arsenides or stibides (LnAs, LnSb, Eu2Sb3, Yb5Sb4), in good yields (70-90%), via metathesis reactions. Mixed lanthanide arsenides and stibides, Ln0.5Ln0.5'E, (LnLn'=DyEr, NdPr; E=As; LnLn'=LaY, TbHo, TbEr, LaHo and PrHo; E=Sb) are made in a similar fashion by combining mixed ianthanide halide powders with Na3As or Na3Sb and initiating the reaction at 800-degrees-C. Solid solutions of LnAs(x)P(y) and LnSbxAsy (Ln=Dy, Sm, Tb; x+y=1) are made analogously using Na3AsxPy and Na3SbxAsy as starting materials. Lanthanide bismuthides (LnBi), can be made from LnCl3 and Na3Bi; however, decomposition to Ln metal and bismuth occurs on trituration with methanol. The lanthanide arsenides, lanthanide stibides, mixed lanthanide arsenides and mixed lanthanide pnictides were characterised by X-ray powder diffraction (XRD), microanalysis, scanning electron microscopy (SEM), energy dispersive X-rays analysis (EDXA), FTIR and magnetic-moment measurements.