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Published on: May 10, 2021
Penta-lanthanum zinc diplumbide, La5Zn1-x Pb2+x (x ≃ 0.6)
Igor Oshchapovsky1, Volodymyr Pavlyuk2, Grygoriy Dmytriv2
1Department of Inorganic Chemistry, Ivan Franko Lviv National University, Kyryla i Mefodia str. 6, 79005 Lviv, Ukraine ; Department of Chemistry and Materials Science Centre, Philipps University of Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany.
Abstract:
The title non-stoichiometric penta-lanthanum zinc diplumbide, La5Zn1-x Pb2+x (x ≃ 0.6), was prepared from the elements in an evacuated silica ampoule. It adopts the Nb5Sn2Si-type structure (space group I4/mcm, Pearson symbol tI32), a ternary ordered superstructure of the W5Si3 type. Among the four independent crystallographic positions, three are fully occupied by La (Wyckoff 16k), La (4b), and Pb (8h) and one is occupied by a statistical mixture [occupancy ratio 0.394 (12):0.606 (12)] of Zn and Pb (4a). The structure is constructed by face-sharing 10-vertex polyhedra around the unmixed Pb sites. These fragments enclose channels of trans-face-sharing tetra-gonal anti-prisms occupied by the disordered Zn and Pb sites.
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