Samarium selenides

The specific susceptibility was measured on polycrystalline NdSe2 and on single crystals parallel and perpendicular to the c axis at 77 to 600 K and 77 to 300 K, respectively. The Curie-Weiss law is obeyed in all cases with the paramagnetic Curie temperatures 0p, the effective moments fiett and the atomic susceptibilities Xa 290 K as follows  

The negative 0p values are ascribed to exchange interactions. The [Xeff value indicates trivalent Nd [6], also see the comparative data on pp. 56/7. An Nd valence of only 2.7 pointing to an appreciable covalent bond component is suggested by measurements of [3] on powdered material at 130 to 470 K. The characteristic data given are 0p = OK, fXeff = 3.35 [Xg, and Xa = 4820x10-6 cm /mol Nd. 

All solid solutions, (Sm,M)Se, Sm(Se,S), and (Sm,M)(Se,S), are treated in this section, without regard to the system number of the rare earth element M or of S, a deviation from the usual Gmelin practice. 

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Samarium selenides. Reductive cleavage of ArSeSeAr by samarium is catalyzed by a great number of metal halides bismuth(III) chloride, cadmium chloride, chromium(IIl) chloride, cobalt(II) chloride, potassium iodide, and titanium(lV) chloride. The resulting samarium arylselenides readily react with various organic halides. 

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