earth elements and M ϭ Mn, Cu, Zn became the subject A series of novel ternary compounds RE 6 MSb 15 has been of the present work emphasizing on their formation, crystal synthesized (a) via arc melting elemental metal ingots (M ؍ structure, and magnetic behavior.
Mn or
Cu) or (b) via reaction sintering cold compacted powder blends (M ؍ Zn). The crystal structure was solved for EXPERIMENTAL La 6 MnSb 15 from single crystal X-ray counter data (La 6 MnSb 15type, Imm2, Z ؍ 2, a ؍ 1.5376, b ؍ 1.9611, c ؍ 0.4314 nm, The compounds Ce 6 MSb 15 (M ϭ Mn, Cu), each with a R F ؍ 0.067 for 923 reflections (͉F 0 ͉ Ͼ 3)). The Rietveld retotal amount of ca. 1 g were prepared by argon arc melting finement of the crystal structure of Ce 6 MnSb 15 using CuK␣from ingots of the high purity elements obtained from X-ray data from a D5000 Siemens diffractometer confirmed Johnson Matthey and Co., UK (99.9 mass%). The mangaatom order and crystal symmetry Imm2 (R I ؍ 0.049, R F ؍ 0.031) and revealed small deficiencies in the Mn site as well nese platelets were surface cleaned in dilute HNO 3 prior as for one of the Sb sites. Employing X-ray powder Guinier to use. Weight losses due to vaporization while melting techniques the new compounds were all found to be isostrucwere less than 2 mass% and were compensated beforehand tural with the La 6 MnSb 15 type. Magnetic measurements perby extra amounts of Mn and Sb. The arc melted buttons formed down to liquid helium temperature give evidence that were then annealed at 600ЊC in vacuum-sealed quartz capilboth compounds Ce 6 MnSb 15 and Gd 6 ZnSb 15 undergo an antiferlaries for 170 h and finally quenched by submerging the romagnetic transition at 7 and 15 K, respectively. Ce 6 ZnSb 15 capsules into cold water. and Pr 6 ZnSb 15 remain paramagnetic in the temperature range Due to the generally high vapor pressure of zinc at eleinvestigated, whereas Sm 6 ZnSb 15 is a Van-Vleck-type vated temperatures, the zinc containing compounds paramagnet.