Nomenclature of coordination compounds

Coordination compounds are named according to the recommendations of lUPAC (see Chap. 7). The basic rules are as follows. 

A coordination entity has a one-word name, formed from the name of the central atom and the names of the ligands. 

If the entity is a cation or neutral, the usual name of the central atom is used (e.g. cobalt). If the entity is an anion, the name of the central atom is changed to end in -ate (e.g. cobaltate). For a few elements, Latin forms are used for anions (e.g. ferrate, cuprate). 

Most neutral ligands have their usual names. A few have special names, e.g. 

Recommendations of the lUPAC committee regarding nomenclature of coordination compounds are contained in their publications.  

Spectroscopy of species in the transition state region was developed in the last fifteen years. In a typical experiment, a femtosecond pulse (1 fs = 10 s) is used to excite the reactant, producing a dissociative state that corresponds to the activated complex, also called the transition state. The frequency of the second pulse is set at the absorption frequency of one of the free fragmentation products, which can be traced by laser-induced fluorescence. It this way, it has been found that the activated complex survives a few hundred of femtoseconds only. 

Nomenclature of Inorganic Chemistry If Recommendations 2000, Edited by J. A. McCle-verty and N. G. Connelly, University of Bristol Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge, CB4 OWE, UK. See also S. F. A. Kettle, Physical Inorganic Chemistry, Oxford University Press, New York 1998, Chapter 3, pp. 24-50. 

Now that we have discussed the various types of ligands and the oxidation numbers of metals, our next step is to learn how to name coordination compounds. The rules for naming ionic coordination compounds are as follows  

The cation is named before the anion, as in other ionic compounds. The rule holds regardless of whether the complex ion bears a net positive or a net negative charge. In the compounds K2[Fe(ClNl)6] and [Co(NH3)4]Cl, for example, we name the and [Co(NH3)4] cations first, respectively. 

Within a complex ion, the ligands are named first, in alphabetical order, and the metal ion is 

The names of anionic ligands end with the letter o, whereas neutral ligands are usually called by the names of the molecules. The exceptions are H2O (aquo), CO (carbonyl), and NH3 (ammine). Table 22.4 lists some common ligands and their nomenclature. 

The oxidation number of the metal is indicated in Roman numerals immediately following the name of the metal. For example, the Roman numeral III is used to indicate the +3 oxidar tion state of chromium in [Cr(NH3)4Cl2]. which is called tetraamminedichlorochromium(III) ion. 

---

Development of Coordination Chemistry Since 1930 Coordination Numbers and Geometries Nomenclature of Coordination Compounds Cages and Clusters Isomerism in Coordination Chemistry Ligand Field Theory Reaction Mechanisms... 

Nomenclature of Coordination Compounds Table 13 Compounds Containing Complex Anions... 

Nomenclature of Coordination Compounds Table 16 Compounds Containing Metal-Metal Bonds... 

We note that the last described approach is seldom used in coordination chemistry. On the contrary, the r -notation of F.A. Cotton is the most widely applied. The nomenclature of coordination compounds according to IUPAC is fully described in Refs. 3 and 10. 

Fernelius, W. C. Nomenclature of Coordination Compounds from Advances In Chemistry Series, No. 8, 9-37, American Chemical Society (1953). International Union of Pure and Applied Chemistry Nomenclature of Inorganic Chemistry, J. Am. Chem. Soc82, 5523 (1960). 

The systematic naming, or nomenclature, of coordination compounds can be complicated to apply, but it is essential to have some familiarity with the basic rules of nomenclature and to be able to work out the structure of a compound from its systematic name. Only a very brief summary of the rules for naming of coordination compounds can be given here, but more detailed accounts are available elsewhere. " ... 

The Nomenclature of Coordination Compounds from Pre-Werner Times to the 1966 lUPAC Report... 

He incorporated these into his suggestions for the nomenclature of coordination compounds. The result was names such as these (33) ... 

ACS Symposium, 1951. As part of the program of the ACS meeting at the time of the lUPAC meeting in New York, a symposium on nomenclature was held. The nomenclature of coordination compounds was discussed in relation to general inorganic nomenclature (10). Rules 1-16 were presented and discussed at that time. A few items are worthy of mention ... 

Nomenclature of Coordination Compounds and Its Relation to General Inorganic Nomenclature... 

The pattern of chemical combination represented by coordination compounds is one of common occurrence. The adoption of a basic plan of nomenclature for this fundamental pattern of chemical combination is desirable. The basic philosophy underlying the various schemes for the naming of coordination compounds is reviewed briefly. The causes of apparent contradictions are discussed. The practices for the nomenclature of coordination compounds suggested by the Commission on the Reform of Inorganic Chemical Nomenclature of the International Union of Chemistry (1940) previously were formulated into a set of rules (1948). These rules are now modified in the light of criticism and further study and are extended to cover situations not previously included. Examples are given to show how the practices prescribed by the rules may be extended. 

---