Darstellung und Struktur weiterer ternärer Phasen mit modifizierter K₈Ge₄₆-Käfigstruktur / Preparation and Crystal Structure of Ternary Phases with a Modified K₈Ge₄₆ Clathrat Structure

Abstract

<jats:p>In the systems K-Al, Ga, In-Si, Ge, Sn each phase of composition K<jats:sub>8</jats:sub>(3B, 4B)<jats:sub>46</jats:sub> was prepared. The crystal structure for K<jats:sub>8</jats:sub>(Al, Ge)<jats:sub>48</jats:sub> and K<jats:sub>8</jats:sub>(Ga, Ge)<jats:sub>46</jats:sub> was determined by X-ray investigations. In the systems Na-Al, Ga-Si, Ge the compounds Na<jats:sub>8</jats:sub>(Al, Ge)<jats:sub>46</jats:sub> (crystal structure determined), Na<jats:sub>8</jats:sub>(Ga, Si)<jats:sub>46</jats:sub> and Na<jats:sub>8</jats:sub>(Ga, Ge)<jats:sub>46</jats:sub> were prepared.</jats:p>

Synthesis and structural characterization of the type-I clathrates K8AlxSn46–xand Rb8AlxSn46–x(x≃ 6.4–9.7)

“…In this report, we discuss the structural aspects of the clathrate phases with compositions K 8 Al x Sn 46-x and Rb 8 Al x Sn 46-x (x ' 8AE1.6), both of which adopt the cubic type-I structure. This work extends the earlier efforts by Krö ner (Krö ner et al, 1998a,b) to structurally characterize K 8 Al 8 Sn 38 and Rb 8 Al 8 Sn 38 , and provides further evidence that helps dispute the structure of K 8 Al 23 Sn 23 assigned by Westerhaus & Schuster (1977) 2. Experimental…”

Structural analysis of Sr8Ga16Ge30 clathrate compound

“…10͒ and K 8 Ga 23 Ge 23 . 11 The interatomic distances calculated from the refined atom positions are shown in Table IV, along with the corresponding distances for the ideal structure. In the case of the ideal and actual structures, for these calculations, the metal guest atoms have been taken to be at the centers of the cages.…”

The Intermetallic Type‐I Clathrate Na8Zn4Ge42

“…This phase thus shows that a Ge‐based type‐I clathrate framework with encaged A atoms can also be realized with the light alkali metal Na. The only other known Ge‐based type‐I clathrates with Na atoms as guests are the Na 8 Tr x Ge 46– x phases with Tr = Al and Ga, and thus, Na 8 Zn 4 Ge 42 also evidences the close relation between the structural chemistry of alkali metal‐zinc‐tetrelides and that of related alkali metal‐trielide‐tetrelides.…”

“…Another type‐I clathrate with Tt = Ge and T = Zn (besides K 8 Zn x Ge 46– x mentioned above) is Ba 8 Zn 8 Ge 38 . Na atoms in guest positions are less frequent but are found in Rb 6 Na 2 Ge 44.89 , Cs 6 Na 2 Zn 4 Ge 42 and Cs 6.40 Na 1.60 Ga 8 Ge 38 , as well as in Na 8 Tr x Ge 46– x with Tr = Al and Ga . Notably, a binary A 8 Ge 46– y □ y phase with A = Na has not been reported, and Na is generally considered not to fit well in the larger cages of a Ge type‐I clathrate host framework .…”