| 释义 |
Madelung constant
Madelung constant A numerical constant αM in terms of which the electrostatic energy U of a three-dimensional periodic crystal lattice of positive and negative  point charges q+, -q-, N in number, is given by the equation below, where d is the nearest-neighbor distance between positive and negative charges and N is large. Knowledge of such electrostatic energies as given by the Madelung constant is of importance in the calculation of the cohesive energies of ionic crystals and in many other problems in the physics of solids. See Ionic crystals Madelung constants for some common ionic crystals | | Madelung | | | Crystal structure | constant, αM | | | Sodium chloride, NaCl | 1.7476 | | | Cesium chloride, CsCI | 1.7627 | | | Zinc blende, α-ZnS | 1.6381 | | | Wurtzite, β-ZnS | 1.641 | | | Fluorite, CaF2 | 5.0388 | | | Cuprite, CuO2 | 4.1155 | | | Rutile, TiO2 | 4.816 | | | Anatase, TiO2 | 4.800 | | | Corundum, Al2O3 | 25.0312 | | The Madelung constants for a number of common ionic crystal structures are given in the table. For these cases d is chosen as the nearest-neighbor distance. See Crystal Madelung constant[′mä·də‚lu̇ŋ ‚kän·stənt] (solid-state physics) A dimensionless constant which determines the electrostatic energy of a three-dimensional periodic crystal lattice consisting of a large number of positive and negative point charges when the number and magnitude of the charges and the nearest-neighbor distance between them is specified. |