Complex Ions Dissolved in Water

It was noted in Section 19.5.5 that metal ions are solvated (hydrated) by binding to water molecules in aqueous solution. Some species in solntion have a stronger tendency than water to bond to metal ions. An example of such a species is cyanide ion, CN , which displaces water molecules from some 

The species that bonds to the metal ion, cyanide in this case, is called a ligand, and the product of the reaction is a complex ion or metal complex. The overall process is called complexation. (See also the discussion of complexation and metal chelates in Chapter 3, Section 3.11.) 

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