Angewandte Chemie International Edition
Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Cover Picture (Angew. Chem. Int. Ed. Engl. 7/1991)
The title picture shows the shell-like structure of a new complex intermetallic compound (LiMgAl2). The picture brings to mind totally different objects like viruses, radiolarians, and space stations. The light blue surface consists of 12 five- and six-membered rings constructed from 76 aluminum atoms. The polygon with 76 corners is also a possible C76 fullerene structure. (For a report by H. Schwarz et al. on the inclusion of helium within the cage formed by C60 and C70, see p. 884). The bonds depicted in green link neighboring Al76 polyhedrons in a three-dimensional network. The perfect dual nature of the structure is shown by the red polyhedron inside Al76, which has 76 surfaces and 40 corners. The inner yellow shell is constructed of all three elements. R. Nesper et al. report on structures of this type, the new descriptions of their chemical bonds, general structural aspects, and the relationships to quasicrystals and other chemical classes of compounds on p. 789.