Citation sequence formulae

It is often inconvenient to represent all the ligand formulae in detail. Abbreviations are often used and are indeed encouraged, with certain provisos. These are the abbreviations should all be written in lower case (with minor exceptions, such as Me, Et and Ph) and preferably not more than four letters with certain exceptions of wide currency, abbreviations should be defined in a text when they first appear in a formula, the abbreviation should be enclosed in parentheses, and its place in the citation sequence should be determined by its formula, as discussed above and particular attention should be paid to the loss of hydrous from a ligand precursor. 

IR-4.2.3 Structural formulae and the use of enclosing marks in formulae IR-4.2.4 Formulae of (formal) addition compounds IR-4.2.5 Solid state structural information IR-4.3 Indication of ionic charge IR-4.4 Sequence of citation of symbols in formulae IR-4.4.1 Introduction IR-4.4.2 Ordering principles IR-4.4.2.1 Electronegativity IR-4.4.2.2 Alphanumerical order IR-4.4.3 Formulae for specific classes of compounds IR-4.4.3.1 Binary species... 

For a sequence of more than four asymmetric carbon atoms, two or more prefixes are used. The sequence of asymmetric carbon atoms is divided so that there is a four-carbon prefix for the carbon atoms closest to the principal function, and so that the other prefixes contain the maximal possible number of asymmetric carbon atoms. In the actual name, the order of citation of the prefixes is to start with the grouping furthest removed from the principal function. The most common examples of compounds requiring this type of compound prefixes are the sugars and glycitols with seven or more carbon atoms, two examples of which are given in the accompanying formulas. 

---