Germanium electronic structure

Herman, F., and J. Callaway Electronic structure of the germanium crystal. 

The NU-Ge-1 exhibits optical absorption effects that are tunable by changing the wall thickness of the germanium framework. The pore structure of this material can be both active and sensitive toward electron-transfer adsorbates. We have observed that the electronic structure of the NU-Ge-1 can be altered in a controllable manner... 

Ans. Mendeleev had used the prefix eka- (Sanskrit word for first) to name elements whose existence he predicted, applying the prefix to a known element in the same periodic group as the predicted element. His eka-boron, eka-aluminum, and e a-silicon were later discovered, confirmed, and named scandium, gallium, and germanium. Elements 104 and 105 were predicted to have electronic structures analogous to Hf and Ta. 

A great number of investigations was dedicated to studying the physical properties of organic compounds of germanium, tin and lead. We discuss here only those that include a comparative study of these compounds as well as studies which verify or develop theoretical concepts of their electronic structure. 

A. N. Egorochkin and M. G. Voronkov, Electronic Structure of Organic Compounds of Silicon, Germanium and Tin, Publishing House of the Siberian Branch of Russian Academy of Sciences, Novosibirsk, 2000 (Russian). 

Stable. In this case the electronic structure ordinarily approximates that of a free-elcctron gas and may be analyzed with methods appropriate to free-electron gases. Again, the crystal structure is the determining feature for the classification. When tin has a tetrahedral structure it is a covalent solid when it has a close-packed white-tin structure, it is a metal. Even silicon and germanium, when melted, become close-packed and liquid metals. 

The rapid developments in theoretical methods and substantial enhancement of computing power over the past decade have had a dramatic impact on all areas of chemistry including organogermanium chemistry. Advances in computational methods applied to germanium chemistry as well as complementary experiments exploring the electronic structure will be discussed. 

The most stable clusters of tin, as well as of the rest of the elements in this group except carbon, are, by far, the nine-atom clusters. As mentioned above, Sng was the first deltahedral cluster to be structurally characterized. While Geg was added very soon after, nine-atom clusters of lead and silicon were found respectively 20 and 30 years later. ° Thus, the following discussion of geometry, charges, cluster-bonding, and electronic structure is valid not only for tin clusters, but also for those of silicon, germanium, and lead. 

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