Networks of icosahedra in the sodium–zinc–stannides Na16Zn13.54Sn13.46(5), Na22Zn20Sn19(1), and Na34Zn66Sn38(1)

SrZn2Sn2 and Ca2Zn3Sn6 — two new Ae–Zn–Sn polar intermetallic compounds (Ae: alkaline earth metal)

“…As it can also be seen from the graphical representations in [55] this comes along with a flattening of the domains around the Cl À anions in face of the cations (with the connecting line as normal to the flattened side). A related shaping of (merged) localization domains and positioning of ELF maxima can also be seen for lone pair like domains of the title compounds, e.g., for 7 J and J and ? 11 .…”

“…Correspondingly, the ring shape I can be seen to represent a strong Sn2-Zn2 bonding interaction in accordance with the short Sn2-Zn2 bond length, whereas the merged domain 7 J at Sn3 remains as a lone pair type domain. Thus the strong interlayer Zn-Sn bonds that are indicated by the short interlayer Zn-Sn distances (2.608(1)Å for Ca 2 Zn 3 Sn 6 and 2.599(3)Å for SrZn 2 Sn 2 ) and confirmed by bonding interactions up to E F resulting in high -ICOHP values, are also reflected by the ELF.…”

“…At an ELF isosurface value of 0.52 as shown in Fig. 12(b) these are included in a merged lone pair type localization domain 7 J with a circular opening.…”

“…With the light alkali metals, Li 2 ZnSn [2,3] and a number of Na-Zn-Sn phases with a rich diversity of polyanionic Zn-Sn substructures are known. The latter include isolated {Sn-Zn-Sn} units [4], networks of fourbonded Zn and Sn atoms [5], and networks of interconnected icosahedral Zn-Sn clusters combined with other structure motifs (clusters or others) [6,7]. For the heavier alkali metals Rb and Cs, intermetallic type-I clathrates A 8 Zn 4 Sn 42 have been studied [8,9].…”

More of the “Fullercages”

“…In quite a few cases, simple electron counting may help understanding the cluster formation, however, usually chemical bonding can only be really understood based on quantum‐mechanical calculations (see Refs. 12–15, for instance). Consequently, we focus on a purely geometrical discussion, the underlying chemical bonding and electronic band structure being beyond the scope of this study.…”