The Clathrate Ba8–xSi46 Revisited: Preparation Routes, Electrical and Thermal Transport Properties1. Issue 2 (4th February 2015)

• Record Type: Journal Article
• Authors: Castillo, Rodrigo; Schnelle, Walter; Bobnar, Matej; Burkhardt, Ulrich; Böhme, Bodo; Baitinger, Michael; Schwarz, Ulrich; Grin, Yuri
• Is Part Of: Zeitschrift für anorganische und allgemeine Chemie. Volume 641:Issue 2(2015)
• Page Start: 206
• Page End: 213
• Publication Date: 2015-02-04
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry -- Periodicals; 540
• DOI: 10.1002/zaac.201500001
• Languages: English
• ISSNs: 0044-2313

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p> The clathrate‐I Ba<sub>8–<italic>x</italic></sub>Si<sub>46</sub> was manufactured from BaSi<sub>2</sub> and α‐Si by high‐pressure high‐temperature synthesis at 5 GPa and 900 °C and by redox reaction from Ba<sub>4</sub>Li<sub>2</sub>Si<sub>6</sub>. The transport properties were measured on specimens from the high‐pressure high‐temperature synthesis. The composition of the Ba<sub>8–<italic>x</italic></sub>Si<sub>46</sub> phase [space group <italic>Pm</italic><inline-formula><alternatives><tex-math notation="tex"><![CDATA[$\bar{3}$]]></tex-math><inline-graphic xlink:href="ark:/27927/pgh3xswffmp" mimetype="image" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /></alternatives></inline-formula><italic>n</italic>, <italic>a</italic> = 10.3051(1) Å] corresponds to <italic>x</italic> = 0.8(2) according to the refined lattice parameter, the value determined from full‐profile refinement of powder X‐ray diffraction data amounts to <italic>x</italic> = 0.73(1), and the chemical analysis results in <italic>x</italic> = 1.0(1), yielding the average composition Ba<sub>7.2(2)</sub>Si<sub>46</sub>. The electrical transport properties of the phase with <italic>x</italic> = 0.8 were determined in the temperature range 2–300 K using a polycrystalline bulk specimen. The material is a metallic conductor with <italic>ρ</italic>(300 K) = 3.3 μΩ m and <italic>S</italic>(300 K) = –6.8 μV K<sup>–1</sup>. The thermal conductivity shows a relatively large – for an intermetallic clathrate – value of about 8 W<bold>·</bold>K<sup>–1</sup> m<sup>–1</sup>.</p> </abstract>