Wiktionary
n. 1 (context chemistry English) any ion containing more than one atom. e.g. sulphate as opposed to sulphide 2 (context chemistry English) any ion in which a central metal atom (normally a transition element) is surrounded by a group of ions or molecules (ligands). e.g. ferricyanide
Usage examples of "complex ion".
The existence of stockpiles of nuclear weapons caused warfare to adopt a new complex ion in the Empire Before when a pretender's House attempted to seize power, the Imperial House would usually destroy the upstart House (as House Windsor did when the pretender Hitler attempted to seize the throne m the decade immediately before the development of atomics), or else be displaced (as House Windsor displaced House Bourbon three centu ties before) But the advent of atomics made the total defeat of a House with a stockpile an impossible task, since it was malterably in the .
Of course, with body fluids under the same pressure, it might be more a matter of complex ion equilibrium than simple solubility.