Structural prefixes, chemical names

See Chart 6 for the structures and recommended names. In these names, the Chemical Abstracts order of prefixes has been followed. Compounds Nos. 30-32 and 34-38 are those which up to now have usually been included in treatises on terpenes. Many of the other structures, however, surely warrant inclusion in the future. 

Use italic type for positional, stereochemical, configurational, and descriptive structural prefixes when they appear with the chemical name or formula. Use a hyphen to separate them from the chemical name. Accepted prefixes include the following ... 

When the structural prefixes cyclo, iso, neo, and spiro are integral parts of chemical names, close them up to the rest of the name (without hyphens) and do not italicize them. 

Chemical formulas describe the simplest atom ratio (empirical formula), actual atom number (molecular formula), and atom arrangement (structural formula) of one unit of a compound. An ionic compound is named with cation first and anion second. For metals that can form more than one ion, the charge is shown with a Roman numeral. Oxoanions have suffixes, and sometimes prefixes, attached to the element root name to indicate the number of oxygen atoms. Names of hydrates give the number of associated water molecules with a numerical prefix. Acid names are based on anion names. Covalent compounds have the first word of the name for the element that is leftmost or lower down in the periodic table, and prefixes show the number of each atom. The molecular (or formula) mass of a compound is the sum of the atomic masses in the formula. Molecules are depicted by various types of formulas and models. 

Carbon Prefix Atoms Name Alkane Formula Chemical Structural Formula ... 

The lists of regulated dangerous goods in transportation include many chemical prefixes that codify the structure of molecules, usually organic. Over time, many conventions have arisen that result in the acceptance of today s somewhat inconsistent scheme. On occasion, these prefixes may be placed in the centre of a chemical name, preceding a functional group or atom, or, very rarely, at the end of a name. 

Nonsystematic names for organic compounds may still be found in the chemical literature and chemical supply catalogs, and so it is important to be somewhat familiar with these as well as with the IUPAC rules. Give the systematic name for (a) isobutane and (b) isopentane, (c) Formulate a rule for the usage of the prefix iso- and predict the structure of isohexane. Structures for these compounds can be found on the Web site for this book. 

Cross references to related group or sub-group entries are also included, with a group list of the names and serial (not page) numbers of the chemicals appearing in Volume 1 which lie within the structural or functional scope of the group entry title. Compounds which are closely similar to, but not in strict conformity with, the group definition are indicated by a prefixed asterisk. 

The systematic nomenclature for the cycloproparenes is confused because the fusion rule (IUPAC Rule A 21.3) requires that at least two rings of five or more members be present before the prefix cyclopropa may be used. Thus while l//-cyclopropa[a]- and -[/ naphthalene are correct for 10 and 11, respectively, 1 //-cyclopropabenzene is incorrect for 1. The Chemical Abstracts service and IUPAC are unanimous in naming 1 as bicyclo-[4.1. Ojhepta-1,3,5-triene la. Thus if the parent member is strictly named, not only does it differ from that of its higher homologues, but also it could be taken to imply a bond localized structure. Throughout this chapter parent 1 and its derivatives 5-9 are referred to as cyclopropabenzenes and numbered as shown for structure 1. 

The names given to the polymers in the following table exemplify elementary aspects of nomenclature. Thus source-based nomenclature places the prefix poly before the name of the monomer, the monomer s name being contained within parentheses unless it is a simple single word. In structure-based nomenclature the prefix poly is followed in parentheses by words which describe the chemical structure of the repeat unit. 

The nomenclature of polymers is somewhat complex, due in part to the fact that the majority of polymers have more than one correct name moreover, in some cases the registered trade names are also used to denote some polymers. The criterion adopted here is to use names that most clearly and simply state the chemical structures of the polymers. The polymers in Tables 1.1a and 1.1b have been named following the basic rules of nomenclature. Thus, the prefix poly is placed before the name of the monomer, and the name of the monomer is set within parentheses unless it is a simple word. In the case of repeating units containing more than one monomer (examples in Table 1.1b), the words contained in parentheses after the prefix poly must describe the chemical structure of the repeating unit. 

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