Raman Lines due to Co-ordination Bond

Abstract

FOLLOWING J. J. Thomson, Kossel, and others, it can be shown that a large number of observed facts about co-ordination compounds can be explained on the assumption that these groups are held by purely electrostatic forces to the central atom. Grimm has been able to calculate the heat of association per molecule of NH₃ surrounding the cation of a simple salt, from a knowledge of the heat of formation of the ammines and the lattice energy of the simple salt. He has shown that for a monovalent cation with an octet shell the heat of association is 14 calories per gram molecule, 28 calories for a divalent ion, and so on. Also, the maximum co-ordination number of an atom can be shown to depend on the relative size of the latter to those of the co-ordination groups.