CHE 112

Nomenclature of Complex Ions

Specifies:	1) quantity & identity of ligands
	2) identity & oxidation number of complexed metal ion

1. Designate the quantity of a monodentate ligand using numeric prefixes: di, tri, tetra, penta, hexa.

2. Designate the quantity of a “complex” ligand using alternative numeric prefixes: bis, tris, tetrakis. Enclose the name of this ligand in ( ). For example, bis(ethylenediamine).

3. For anion ligands, substitute “-o” for the normal ending. e.g.,

Cl^-	chloro	CO3^2-	carbonato
OH^-	hydroxo	C2O4^2-	oxalato
CN^-	cyano	SCN^-	thiocyanato

4. Names of molecule ligands usually are not changed. Exceptions are

H2O	aqua
NH3	ammine
CO	carbonyl

5. Ligands are named in alphabetical order if more than one type. Numeric prefixes are ignored while alphabetizing.

6. Then, the complexed metal ion is named, followed by its oxidation number in ( ). If the complex ion is an anion, the suffix –ate is added to the metal’s name – and, if the metal’s abbreviation is from Latin, use its Latin name with the –ate suffix. (However, this is not done for mercury.)

Ag	argentum	Au	aurum
Cu	cuprum	Fe	ferrum
Pb	plumbum	Sn	stannum

Examples:

[Pt(NH3)Cl3]^-	amminetrichloroplatinate (II)
[AgCl2]^-	dichloroargentate (I)
[Zn(H2O)4]Br2	tetraaquazinc (II) bromide (note, this is a coordination compound)