Unformatted text preview: Authors: Rolf Unterleitner & Doug Kent
Nomenclature for Compounds Containing Transition Metal Complex Ions:
1. As in any ionic compound, the cation is named before the anion.
2. When naming a complex ion (the part in [ ]'s):
a. the ligands are named first; if there are two or more different ligands,
they are named alphabetically by the name. In the formula the metal is first then the
anions in alpha. order and last neutral molecules in alpha. order. The alpha. order with the
letter in the formula not the name. Example NH3 would be the N not the a in ammine)
b. prefixes are used to denote the number of each ligand: di (2), tri (3), tetra (4), penta
(5), hexa (6), etc.;
for polydentate ligands with di or tri in their name use bis (2), tris (3).
Also put the name in (), e.g. tris(ethylenediamine);
prefixes are ignored in alphabetizing ligands, e.g. tribromo comes before dichloro
c. the metal ion is named last, although it is shown first in the complex and is a cation
d. if the complex ion is positive (a cation) or neutral, the metal is named as usual,
e.g. Fe = iron, Co = cobalt, Zn = zinc, etc.
e. if the complex ion is negative (an anion), an ate is added or it replaces -ium and -ese ending
of the of the metal's name, e.g. Zn = zincate, Co =cobaltate, etc.
Note too the ium and ese endings of the metals are left off, Cr=chromate. Mn=manganate
in some cases common names must be used, e.g.
Fe = ferrate (not "ironate"),
Ag = argentate (not "silverate"),
Cu = cuprate(not "copperate"),
Au = aurate (not "goldate"),
Sn = stannate(not "tinate")
f. in all cases, the oxidation state of the metal is denoted by a Roman
numeral in parentheses after the name of the metal, e.g.
Fe2+ = iron (II) in a cationic or neutral complex, ferrate (II)
in an anionic complex
3. Ligand names
a. monodentate ligands: attach to central metal atom in only one place
(1) In general if the anion name ends in -ite or -ate the -e is changed to an -o
as a ligands, e.g. CO32- = carbonato (not "carbonate")
(2) For most cases you need to know when the name ends in -ide the ide is changed to -o
as a ligands, e.g. F- = fluoro (not "fluoride"), Cl- = chloro (not "chloride"),
OH- = hydroxo (not "hydroxide") etc.
(3) Linkage isomers: In some cases the ligand can be attached to the metal by different atoms
the three you'll need to know are:
1) NO2- when seen as (ONO) in complex = nitrito or nitrito-O- (attached to the O)
seen as (NO2) in complex the ligand = nitro or nitrito-N- (attached to the N)
2) CN- when seen as (CN) is cyano (attached to the C)
seen as (NC) is isocyano or cyano-N- (attached to the N)
3) SCN- when seen as (SCN) is thiocyanato or thiocyanato-S- (attached to the S) seen as (NCS) is isothiocyanato or thiocyanato-N- (attached to the N)
(4) neutral ligands: H2O = aqua, NH3 = ammine, NO = nitrosyl, CO = carbonyl
b. bidentate ligands: attach to central metal atom at two places
(1) C2O42- = oxalato (not "oxalate;" see Rule 3a(2) above)
(2) NH2CH2CH2NH2 = ethylenediamine (en) (attaches at the two nitrogens)
c. tridentate ligand attaches to central metal ion at three places:
NH2CH2CH2NHCH2CH2NH2 = diethylenetriamine (dien)
(attaches at the three nitrogens)
d. hexadentate ligand attaches to central metal ion at six places:
ethylenediaminetetraacetato = EDTA4Examples: On next page
[Ag(NH3)2]Cl diamminesilver(I) chloride
[PtCl2(NH3)2] diamminedichloroplatinum(II) (Note: No space between ligand names)
[CoBr2ONO(NH3)3]NO3 triamminedibromonitritocobalt(IV) nitrate or
K2[Cu(NC)4(NH3)2] potassium diamminetetraisocyanocuprate(II) or
[Cu(en)2(H2O)2]2CO3 diaquabis(ethylenediamine)copper(I) carbonate
Na2[Fe(C2O4)2(NO)2] Sodium dioxalatodinitrosylferrate(II) ...
View Full Document
- Spring '08
- Chemistry, NH3, ligands, central metal ion, complex ion, central metal atom