A complex ion is a species in which a central
metal ion is attached to a group of surrounding ions or molecules
by coordinate covalent bonds. The surrounding species are called
ligands. Within a ligand, the atoms that are directly
attached to the metal ion (or atom) are called donor atoms. Most
ligands contain a single donor atom (monodentate), but some contain
two donor atoms (bidentate), six donor atoms (hexadentate), or
another combination of donor atoms. A complex ion that...