title: Synthesis, Characterization, and Bonding of Heteroatomic Clusters: Na(13)Cd(20)E(7) (E = Pb, Sn), a Further Example of a Structure Containing Empty Icosahedra without an Element of Group 13.
abstract: The compounds Na(13)Cd(20)E(7) (E = Pb, Sn) were made in nearly 100% yield by quenching the melts of appropriate mixtures of elements sealed in niobium containers. They crystallize in the cubic space group Im&thremacr;, Z = 4, with a = 15.992(2) and 15.790(4) Å for E = Pb and Sn, respectively. The Cd/E part of the structure is a framework of heavily fused monocapped truncated trigonal prisms. Twelve-bonded icosahedra are nested in cavities of the framework. This is the second example of a structure containing empty icosahedra made without the participation of an element of the boron group. The sodium cations occupy the space between the clusters and inside the 13-atom polyhedra.
authors.affiliation: Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556.
authors.forename: Evgeny
authors.initials: E
authors.lastname: Todorov
authors.forename: Slavi C.
authors.initials: SC
authors.lastname: Sevov