ic502326j_si_002.cif (1.61 MB)
Download fileLithiation-Induced Zinc Clustering of Zn3, Zn12, and Zn18 Units in Zintl-Like Ca∼30Li3+xZn60–x (x = 0.44–1.38)
dataset
posted on 2015-02-02, 00:00 authored by Qisheng LinZinc clusters are not common for
binary intermetallics with relatively low zinc content, but this work
shows that zinc clustering can be triggered by lithiation, as exemplified
by Ca∼30Li3+xZn60–x, P6/mmm, Z = 1, which can be directly converted from CaZn2. Two end members of the solid solution (x = 0.44 and 1.38) were established and structurally characterized
by single-crystal X-ray diffraction analyses: Ca30Li3.44(6)Zn59.56(6), a = 15.4651(9)
Å, c = 9.3898(3) Å; Ca30.45(2)Li4.38(6)Zn58.62(6), a = 15.524(3)
Å, c = 9.413(2) Å. The structures of Ca∼30Li3+xZn60–x feature a condensed anionic network of Zn3 triangles, lithium-centered Zn12 icosahedra, and arachno-(Zn,Li)18 tubular clusters that are surrounded
respectively by Ca14, Ca20, and Ca30 polyhedra. These polyhedra share faces and form a clathrate-like
cationic framework. The specific occupation of lithium in the structure
is consistent with theoretical “coloring” analyses.
Analysis by the linear muffin-tin orbital (LMTO) method within the
atomic sphere approximation reveals that Ca∼30Li3+xZn60–x is a metallic, Zintl-like phase with an open-shell electronic structure.
The contribution of Ca–Zn polar covalent interactions is about
41%.