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Title: Ca 2 Ga 4 Ge 6 and Ca 3 Ga 4 Ge 6 : Synthesis, Structure, and Electronic Properties
Abstract During the search for transition metal‐free alkyne hydrogenation catalysts, two new ternary Ca−Ga−Ge phases, Ca2Ga4Ge6(Cmc21, a=4.1600(10) Å, b=23.283(5) Å, c=10.789(3) Å) and Ca3Ga4Ge6(C2/m, a=24.063(2) Å, b=4.1987(4) Å, c=10.9794(9) Å, β=91.409(4)°), were discovered. These compounds are isostructural to the previously established Yb2Ga4Ge6and Yb3Ga4Ge6analogues, and according to Zintl‐Klemm counting rules, consist of anionic [Ga4Ge6]4−and [Ga4Ge6]6−frameworks in which every Ga and Ge atom would have a formal octet with no Ga−Ga or Ga−Ge π‐bonding. These compounds are metallic, based on temperature dependent electrical resistivity and thermopower measurements for Ca3Ga4Ge6, along with density functional theory calculations for both phases. Unlike the highly active 13‐layer trigonal CaGaGe phase, these new compounds exhibit minimal activity in the semi/full alkyne hydrogenation of phenylacetylene, which is consistent with previous observations that the lack of a formal octet for framework atoms is essential for catalysis in these Zintl‐Klemm compounds.  more » « less
Award ID(s):
2011876
PAR ID:
10582595
Author(s) / Creator(s):
; ; ; ; ;
Publisher / Repository:
Wiley
Date Published:
Journal Name:
Zeitschrift für anorganische und allgemeine Chemie
Volume:
648
Issue:
15
ISSN:
0044-2313
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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