| 1 | Author
| Z. Naturforsch | Requires cookie* | | Title
| Bonding in an Unusual Nickel Carbide  | | | Abstract
| The bonding in an unusual nickel carbide polymer network synthesized by Musanke and Jeitschko is analyzed using qualitative, band-structure calculations in the framework of extended Hiickel tight-binding theory. The carbide features infinite, one-dimensional, vertex-sharing chains of Ni squares. Each square is centered by a carbon and flanked by C: units. -In this electron-rich polymer, the Ni atoms act as electron acceptors through their s and p orbitals. The orbital interaction schemes reveal that there is little Ni-Ni bonding and essentially no Ni to C2 back-donation. Molecular orbital interaction diagrams of some molecular models are used to describe the bonding in ^[N i^C s]8 -. We also discuss the stability of the planar building block of the polymer, (CNi.;)4"' (which resembles planar CH4) with respect to a "tetrahedral" alternative and we do so for the extended ^ [ N i3C]4-and ^[Ni.^C?]8-chains. In each model case the tetrahedral alternative is favored, and there is no sign of stabilization of a crucial C L4 orbital. Such stabilization is partially achieved through bonding to two Ca axial to the C in the center of the Ni4 ring, but it takes the entire inter-chain calcium network to effect the observed stabilization. | | |
Reference
| Z. Naturforsch. 53b, 322—332 (1998); received November 4 1997 | | |
Published
| 1998 | | |
Keywords
| Carbides, Molecular Orbitals, Electronic Structure, Metal Carbides, Square-Planar Carbon | | |
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| default:Reihe_B/53/ZNB-1998-53b-0322.pdf | | | Identifier
| ZNB-1998-53b-0322 | | | Volume
| 53 | |
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