The Madelung constants of slices and chains, with an application to the CdI2structure

The Ewald expression for the electrostatic lattice energy is adapted to the calculation of this energy in slices and chains.Application to the CdL structure gives as a new value for the Madelung constant of the Bozorth structure 4.382, of the Hassel structure 4.384 and of a (0001) slice 4-377.The electrostatic attraction energy between the slices in the Bozorth structure amounts to --0.5 kcal.mol.-~, the repulsion energy + 1-6 kcal.mol.-~ (based on Pinsker's value of the total repulsion energy).The van der Waals energy (--8-0 kcal.mol.-~ according to Pinsker) far outweighs the other energies.