A coordination complex is a substance in which a metal atom or ion accepts electrons from (andthus associates with) a group of neutral molecules or anions called ligands. A complex can be an anion, a cation ion, or a neutral molecule. Coordination compounds are neutral substances (i.e.uncharged) in which at least one ion is present as a complex.

Nomeclature of Co-ordination compounds

Read the following steps carefully (don’t skip one)

  • When naming coordination compounds, always name the cation before the anion. Thisrule holds regardless of whether the complex ion is the cation or the anion. (This is justlike naming an ionic compound.)
  • In naming the complex ion:

a. Name the ligands first, in alphabetical order, and then name the metal atom or ion. Note: The metal atom or

ion is written before the ligands in the chemical  formula.

b.The names of some common ligands are listed:

***Ligands = attached (to central metal atom/ion) atoms or molecules



This Educational Post was submitted by

Tomal Roy
M.Sc. Student
Dept. of Chemistry