Definition of Donor atom symbol

1. A polydentate ligandpossesses more than one donor site, some or all of which may be involved in coordination. To indicate the points of ligation, a system is needed. The general and systematic system for doing this is called the kappa convention: single ligating atom attachments of a polyatomic ligand to a coordination centre are indicated by the italic element symbol preceded by a Greek kappa, . In earlier practice, the different donors of the ligand were denoted by adding to the end of the name of the ligand the italicized symbol(s) for the atom or atoms through which attachment to the metal occurs.