naming complexes
DESCRIPTION
Chloride, Cl- is one element Naming complexes Definition: A complex is a central metal ion surrounded by ligands Examples: [Cu(H2O)6]2+ and [CuCl4]2- Round brackets, ( ) are used around ligands comprising of more than one element such as: Water (H2O), ammonia (NH3), hydroxide ions (OH-) Square brackets, [ ] are used to enclose the complex, with the overall charge written outside Chloride, Cl- is one elementTRANSCRIPT
Definition: A complex is a central metal ion surrounded by ligands
Examples: [Cu(H2O)6]2+ and [CuCl4]2-
Round brackets, ( ) are used around ligands comprising of more than one element such as:
Water (H2O), ammonia (NH3), hydroxide ions (OH-)
Square brackets, [ ] are used to enclose the complex, with the overall charge written outside
Chloride, Cl- is one element
The name of a complex gives you information about:
The number of each type of ligand The identity of each ligand The identity of the central metal ion and its oxidation
state
Example: [Cr(H2O)4(OH)2]+
4 water (H2O) ligands and 2 hydroxide (OH-) ligands Chromium(III) ion, Cr3+
When there are two or more ligands around the central metal ion, the number is shown by a prefix
Example: [Cu(H2O)6]2+ Name: Hexa
Number of ligands Prefix2 Di3 Tri4 Tetra5 Penta6 Hexa
The identity of each type of ligand is shown by a name This name is not identical to the name of the ligand
Example: [Cu(H2O)6]2+ Name: Hexaaqua
Ligand Name in complexWater Aqua
Ammonia AmmineChloride Chloro
Hydroxide HydroxoCyanide Cyano
The name of the metal changes depending on whether the complex is positively or negatively charged
If the complex is positively charged, the metal is identified by its normal name, with the oxidation state shown in brackets
Example: [Cu(H2O)6]2+ Name: Hexaaquacopper(II)
Example: [Cu(H2O)6]+ Name: Hexaaquacopper(I) Example: [Co(H2O)6]2+ Name: Hexaaquacobalt(II)
If the complex is negatively charged, the oxidation state of the metal is still shown in brackets
But the ending of the metal’s name has the suffix ate added to it
Metal Name in negatively charged complex
Chromium ChromateCobalt CobaltateCopper Cuprate
Iron FerrateManganese Manganate
Metal Name in negatively charged complex
Chromium ChromateCobalt CobaltateCopper Cuprate
Iron FerrateManganese Manganate
Nickel NickelateSilver Argentate
Vanadium Vanadate
It is acceptable to have two letter a’s next to each other, such as hexaaqua or hexaamine
Formula Name[Ag(NH3)2]+ Diamminesilver(I)
[Co(H2O)6]2+ Hexaaquacobalt(II)
[Co(NH3)6]2+ Hexaamminecobalt(II)
[CoCl4]2- Tetrachlorocobaltate(II)
[AgCl2]- Dichloroargenate(I)
[Fe(H2O)6]2+ Hexaaquairon(II)
[Ag(CN)2]- Dicyanoargenate(I)
If two or more ligands are present in a complex, they are named in alphabetical order
It is the name of the ligand which is written in alphabetical order, not the numbering prefix
Examples:
[Cu(H2O)5(OH)]+ Pentaaquahydroxocopper(II)
[Cu(H2O)2(NH3)4]2+ Tetraamminediaquacopper(II)
[Fe(H2O)4(OH)2]+ Tetraaquadihydroxoiron(III)
When you write the formula of a complex:
First write the symbol of the central metal ion Then write the symbols of the ligands in alphabetical
order Include brackets and work out the charge on the outside
Example: Tetraaquadichlorochromium(III) ion
[CrCl2(H2O)4]+ Not [Cr(H2O)4Cl2]+
First write the symbol of the central metal ion Then write the symbols of the ligands in alphabetical
order Include brackets and work out the charge on the outside
Name FormulaDiaquasilver(I) [Ag(H2O)2]+
Hexaaquavanadium(III) [V(H2O)6]3+
Tetracyanonickelate(II) [Ni(CN)4]2-
Tetrachloroferrate(II) [FeCl4]2-
Diaquatetrahydroxochromate(III) [Cr(H2O)2(OH)4]-
Triaaquatrihydroxocuprate(II) [Cu(H2O)3(OH)3]-