Fe-Fe bonding in the rhombic Fe cores of the Zintl clusters [FeE] (E = Sn and Pb).

We report here the synthesis and characterization of two endohedral Zintl-ion clusters, [FeSn] and [FePb], which contain rhombic Fe cores. The Fe-Fe bond lengths are all below 2.5 Å, distinctly shorter than in the corresponding Cu clusters, indicating the presence of Fe-Fe bonding.

Snap-shots of cluster growth: structure and properties of a Zintl ion with an Fe core, [FeSn].

The endohedral Zintl-ion cluster [FeSn] contains a linear Fe core with short Fe-Fe bond lengths of 2.4300(9) Å. The ground state is a septet, with significant σ and π contributions to the Fe-Fe bonds.

Synthesis and characterisation of the ternary intermetalloid clusters {M@[As(ZnMes)]} (M = Nb, Ta) from binary [M@As] precursors.

The development of rational synthetic routes to inorganic arsenide compounds is an important goal because these materials are finding applications in many areas of materials science. In this paper, we show that the binary crown clusters [M@As] (M = Nb, Ta) can be used as synthetic precursors which, when combined with ZnMes, generate ternary intermetalloid clusters with 12-vertex cages, {M@[As(ZnMes)]} (M = Nb, Ta). Structural studies are complemented by mass spectrometry and an analysis of the electronic structure using DFT.