Nd₂[MoC₂] and RE

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• 作者：Enkhtsetseg Dashjav ; Yurii Prots ; Guido Kreiner ; Walter Schnelle ; Frank R. Wagner ; Rü ; diger Kniep
• 关键词：Carbometalate ; Ternary carbide ; Chemical bonding analysis ; COHP
• 刊名：Science and Technology of Advanced Materials
• 出版年：2007
• 出版时间：July 2007
• 年：2007
• 卷：8
• 期：5
• 页码：364-370
• 全文大小：397 K

文摘

Four new ternary rare-earth-metal carbometalates, Nd₂[MoC₂] and RE₂[WC₂] with RE=Ce, Pr, Nd, have been synthesized by argon arc melting and subsequent heat treatment at 1170 K for 30 days. They crystallize with the Pr₂[MoC₂] structure type with isolated C⁴⁻ species and are typical carbometalates with (i) low metal-to-carbon ratio, (ii) tetrahedral coordination of the transition metals (T) by carbon, and (iii) a polyanionic network . According to resistivity measurements the compounds are bad metals. Volume chemistry and magnetic susceptibility measurements indicate Pr³⁺, Nd³⁺, and Ce⁴⁺ species, respectively. In the latter case, the additional electron is not transferred to the polyanionic network, instead it mainly populates the Ce partial structure.