Nomenclature of Coordination Compounds: Practice and Examples

Nomenclature of Coordination Compounds

Introduction to Coordination Compounds

Coordination compounds, also known as complex compounds, consist of a central metal atom or ion bonded to surrounding molecules or ions called ligands. The systematic naming of these compounds follows IUPAC rules to ensure clarity and consistency in chemical communication.

• Coordination Compound: A chemical species formed by a central metal ion and surrounding ligands.

• Ligand: An ion or molecule that binds to a central metal atom to form a coordination complex.

• Examples: $[Fe(CN)_6]^{4-}$, $[Cu(NH_3)_4]^{2+}$

General Rules for Naming Coordination Compounds

• Name the ligands first (in alphabetical order), followed by the metal ion.

• Prefixes (di-, tri-, tetra-, etc.) indicate the number of each ligand.

• Anionic ligands often end in '-o' (e.g., chloro, cyano).

• Neutral ligands usually retain their molecule name (e.g., aqua for H2O, ammine for NH3).

• Oxidation state of the metal is indicated in Roman numerals in parentheses.

• If the complex ion is an anion, the metal name ends in '-ate'.

Examples of Coordination Compound Nomenclature

The following table provides examples of chemical formulas for coordination compounds and their systematic names. This is essential practice for mastering the nomenclature rules in General Chemistry.

Br.	Formula	Name
1	Na[Cu(S2O3)2]	Sodium bis(thiosulfato)cuprate(II)
2	K[Co(SCN)4]	Potassium tetrathiocyanatocobaltate(II)
3	Cs2[Co(NO3)4]	Caesium tetranitratocobaltate(II)
4	Mg[Fe(C2O4)2]	Magnesium bis(oxalato)ferrate(II)
5	Pd(SO3)2	Palladium(II) sulfite
6	Fe3[Cu(CN)4]2	Iron(III) bis(tetracyanocuprate(II))
7	Na2[Pb(OH)4]	Sodium tetrahydroxoplumbate(II)
8	Ca[CuCl4]	Calcium tetrachlorocuprate(II)
9	Li3[Fe(CN)6]	Lithium hexacyanoferrate(III)
10	[Cu(H2O)4SO4]	Tetraaquacopper(II) sulfate
11	[CoCl2(NH3)4]Cl	Tetrammine dichlorocobalt(III) chloride
12	[Mn(CO)5Br]	Pentacarbonylbromomanganese(I)
13	Na2[Fe(CN)5NO]	Sodium nitroprusside
14	[Re(CO)5NS][SbF6]	Pentacarbonyl(nitrosyl)sulfidorhenium(V) hexafluoroantimonate
15	K[AgF4]	Potassium tetrafluoroargentate(III)
16	K2[NiF6]	Potassium hexafluoronickelate(IV)
17	Na[AlCl4]	Sodium tetrachloroaluminate(III)
18	Cs[ICL4]	Caesium tetrachloroiodate(III)
19	K[Au(OH)4]	Potassium tetrahydroxoaurate(III)
20	K[CrOF4]	Potassium oxotetrafluorochromate(VI)
21	K[Cu(CN)2]	Potassium dicyanocuprate(I)
22	Na[BH(OCH2CH3)3]	Sodium tris(ethoxy)methylborate
23	[Ti(H2O)6]Cl3	Hexaaquatitanyl(III) chloride
24	K2[Zn(CN)4]	Potassium tetracyanozincate(II)
25	[CuCl2(CH3CH2NH2)2]	Dichlorobis(ethylamine)copper(II)
26	[V(H2O)6]PO4	Hexa-aquavanadyl(III) phosphate

Key Points in Coordination Compound Nomenclature

• Ligand names are listed alphabetically, not by quantity.

• Prefixes (di-, tri-, tetra-) are used for multiple identical ligands.

• Oxidation state of the central metal is always specified in Roman numerals.

• Complex anions have the metal name ending in '-ate'.

• Examples: $[Fe(CN)_6]^{4-}$ is called hexacyanoferrate(II).

Example: Naming a Complex Compound

• Formula: $K_2[NiF_6]$

• Step 1: Identify the ligands: six fluoride ions (F-).

• Step 2: Name the ligand: fluoro.

• Step 3: Name the metal: nickel.

• Step 4: Determine the oxidation state: Nickel(IV).

• Step 5: Combine: Potassium hexafluoronickelate(IV).

Additional info:

• This table is a practice exercise for students to master the nomenclature of coordination compounds, a key topic in General Chemistry (Chapter 24: Transition Metals and Coordination Compounds).

• Understanding these rules is essential for interpreting chemical literature and communicating chemical information accurately.