RESUMEN
A disproportionation process of a metastable AlCl solution with a simultaneous ligand exchange-Cl is substituted by N(SiMe(3))(2)-leads to a [Al(69)[N(SiMe(3))(2)](18)](3-) cluster compound that can be regarded as an intermediate on the way to bulk metal formation. The cluster was characterized by an X-ray crystal structural analysis. Regarding its structure and the packing within the crystal, this metalloid cluster with 4 times more Al atoms than ligands is compared to the [Al(77)N(SiMe(3))(2)](20)](2-) cluster that has been published four years ago. Although there is a similar packing density of the Al atoms in both clusters as well as in Al metal, the X-ray structural analysis shows significant differences in topology and distance proportions. The differences between these-at a first glance almost identical-Al clusters demonstrate that results of physical measuring, e.g., of nanostructured surfaces which carry supposedly identical cluster species, have to be interpreted with great caution.
RESUMEN
A "naked" aluminum atom links two aluminum tetrahedra in the [Al(7){N(SiMe(3))(2)}(6)](-) ion (see picture), which results from the reaction of a metastable AlCl solution with LiN(SiMe(3))(2) and crystallizes with [Li(OEt(2))(3)](+) as cation. This unique structure among molecular metal atom clusters represents a small but characteristic section of cubic close-packed aluminum.
RESUMEN
A doubly capped In(6) octahedron characterizes the structure of the dark green octaindane (tBu(3)Si)(6)In(8) (see picture), which is obtained from (C(5)Me(5))In and tBu(3)SiNa in pentane at -78 degrees C. In1/In1' are the capping atoms, and In2/In2' form the apexes of the stretched In(6) octahedron. Thus, in agreement with the results of ab initio calculations, the compound can be classified as a hypoprecloso-indane.