Madelung Constants(A
) for Common Crystal Lattices*
| Structure | Constant |
|---|---|
| Sodium chloride | 1.75 |
| Cesium chloride | 1.76 |
| Zinc blende | 1.64 |
| Wurtzite | 1.64 |
| Fluorite | 5.04 |
| Rutile | 4.82** |
| Corundum | 25.03** |
* The Madelung constant, A, is used in the equation E = AZ 2e 2/r, where r is the sum of the ionic radii, e is the charge on an electron, and Z is the highest common denominator of the absolute values of the integral charges on the ions (e.g., for MgCl2, Z = 1; for CaO, Z = 2).
** Depends on exact structure.
Reference: Huheey, pps. 99-134.