Rule 1: To name a co-ordination compound, no matter whether the complex ion is the cation 1`or the anion, always name the cation before the anion.
Rule 2: Part (a) Name the ligand first, in alphabetical order, then the metal atom or ion.
Part (b) For anionic ligands end in “—o—”. For anions that end in “—ide—” (e.g. chloride), “—ate—” (e.g. sulfate, nitrate) and “—ite—” (e.g. nitrite), change the ending as follows:
-ide —→ -o, -ate —→ -ato, -ite —→ -ito
Part (c) For neutral ligands, the common name of the molecule is used e.g. H2NCH2CH2NH2 (ethylenediamine). Important exceptions: For H2O —→ aqua, NH3 —→ ammine, CO —→ carbonyl and N2 and O2 are called dinitrogen and dioxygen.
Anionic ligands |
Neutral ligands |
Br– — Bromo |
NH3 – ammine |
F– — Fluoro |
H2O – aqua |
O2– — Oxo |
NO – nitronyl |
OH– — Hydroxo |
CO – Carbonyl |
CN– — Cyano |
O2 – Dioxygen |
C2O42– — Oxalato |
N2 – Dinitrogen |
CO32– — Carbonato |
H2NH2C
|
H2NH2C — ethylene diamine
|
|
CH3COO– — aceto |
Rule 3: Greek prefixes are used to designate the number of each type of ligand in the complex ion, di, tri and tetra-. If the ligand already contains a Greek prefix (e.g. ethylendiamine) if it is polydenate ligands the prefixes, bis-, tris-, tetrakis-, pentakis- are used instead.
Rule 4: After naming the ligand, name the central metal. If the complex ion is a cation, metal is named same as the element. But if the complex is an anion, the name of metal ends with the suffix -ate for Latin name.
Rule 5: The oxidation state of the metal in the complex is given as a roman numeral in parentheses.
Home