Bonding alkali metals

Group 15 Alkali Metal Bonded Complexes 2.01.4.1 N-M Bonded Complexes... 

The Alkali Metals.—Bonds of the alkali metals with all nonmetals are essentially ionic (with more than 50 percent ionic character—electronegativity difference greater than 1.7) except for Li—I, Li—C, and Li—S, with about 43 percent ionic character. 

Germanium-carbon multiple bonds, formation, 3, 709 Germanium-chalcogen bonds, reactivity, 3, 745 Germanium complexes with alkali metal bonds, 3, 748 with Isis // -arcnc chromium heteroatoms, 5, 340 with chromium carbonyls, 5, 208 coupling reactions, 3, 711 with CpMoCO, 5, 463... 

Group 11 alkali metal bonded complexes, Group 1-Group 11, 2, 50... 

Group 14 alkali metal bonded complexes Group 1-Group 14, 2, 55 Zintl clusters, 2, 24... 

III. REACTIONS OF GERMANIUM AND TIN DERIVATIVES CONTAINING THE ELEMENT-ALKALI METAL BOND... 

Although the first bis(iminophosphorano)methanides were reported by Elsevier,15 the first structurally characterised examples were reported by Cavell.16 Solvent-free 1 and 2 were prepared from the reaction between the parent methane and lithium or sodium bis(trimethylsilyl)amides in aromatic solvents. By avoiding Lewis base solvents such as ethers, dimeric complexes were isolated. Treatment with excess quantities of alkali metal amide did not effect a second deprotonation, even under reflux conditions over days, which was attributed to the less basic nature of amides compared to alkyls (see section 3.2 below). In addition to the expected methanide-alkali metal bonds, methine C H — Li interactions were observed in 1 in the solid state but the analogous C-H — Na interactions appeared to be weak in 2. 

Prior to the early 1990s, all structural studies of alkali-metal chemisorption found the adatom located at high coordination sites at which the alkali-metal atom is bound in three- or four-fold hollow sites. A comprehensive survey of alkali-metal adsorption studies prior to 1988 may be found in the book edited by Bonzel (Bonzel et al., 1989). Several more recent LEED, SEXAFS and X-ray studies have implicated low coordination (top) sites, as in the case of Cu(lll)p(2x2)-Cs, or substitutional behavior. These results may signal that the current understanding of the alkali-metal bonding at surfaces is incomplete. 

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