3 IUPAC Nomenclature of Organic Chemistry

84 Pages·2011·2.7 MB·English

Revised Edition: 2016
ISBN 978-1-280-29585-0
© All rights reserved.
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Table of Contents

Chapter 1 - IUPAC Nomenclature
Chapter 2 - IUPAC Nomenclature of Inorganic Chemistry
Chapter 3 - IUPAC Nomenclature of Organic Chemistry
Chapter 4 - International Union of Pure and Applied Chemistry
Chapter 5 - International Chemical Identifier
Chapter 6 - Cahn–Ingold–Prelog Priority Rules
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Chapter 7 - Nomenclature of Monoclonal Antibodies
Chapter 8 - Chemical Compounds with Unusual Names
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Chapter- 1
IUPAC Nomenclature

A chemical nomenclature is a set of rules to generate systematic names for chemical
compounds. IUPAC nomenclature is worldwide the most used chemical nomenclature.
It is developed and kept up to date under the auspices of the International Union of Pure
and Applied Chemistry (IUPAC). The rules for naming organic and inorganic compounds
are contained in two publications, known as the Blue Book and the Red Book respect-
tively. A third publication, known as the Green Book, describes the recommendations for
the use of symbols for physical quantities (in association with the IUPAP), while a fourth,
the Gold BooWk, contains the definitions of a largeT number of technical terms used in
chemistry. Similar compendia exist for biochemistry (the White Book, in association with
the IUBMB), analytical chemistry (the Orange Book), macromolecular chemistry (the
Purple Book) and clinical chemistry (the Silver Book). These "colour books" are
supplemented by shorter recommendations for specific circumstances which are
published from time to time in the journal Pure and Applied Chemistry.
Aims of chemical nomenclature
The primary function of chemical nomenclature is to ensure that a spoken or written
chemical name leaves no ambiguity as to what chemical compound the name refers: each
chemical name should refer to a single substance. A less important aim is to ensure that
each substance has a single name, although the number of acceptable names is limited.
Preferably, the name also conveys some information about the structure or chemistry of a
compound. CAS numbers form an extreme example of names that do not perform this
function: each CAS number refers to a single compound but none contain information
about the structure.
The form of nomenclature used depends on the audience to which it is addressed. As
such, no single correct form exists, but rather there are different forms that are more or
less appropriate in different circumstances.
A common name will often suffice to identify a chemical compound in a particular set of
circumstances. To be more generally applicable, the name should indicate at least the
chemical formula. To be more specific still, the three-dimensional arrangement of the
atoms may need to be specified.
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In a few specific circumstances (such as the construction of large indices), it becomes
necessary to ensure that each compound has a unique name: this requires the addition of
extra rules to the standard IUPAC system (the CAS system is the most commonly used in
this context), at the expense of having names which are longer and less familiar to most
readers. Another system gaining popularity is the International Chemical Identifier—
while InChI symbols are not human-readable, they contain complete information about
substance structure. That makes them more general than CAS numbers.
The IUPAC system is often criticized for the above failures when they become relevant
(for example in differing reactivity of sulfur allotropes which IUPAC doesn't
distinguish). While IUPAC has a human-readable advantage over CAS numbering, it
would be difficult to claim that the IUPAC names for some larger, relevant molecules
(such as rapamycin) are human-readable, and so most researchers simply use the informal
names.
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History
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First page of Lavoisier's Chymical Nomenclature in English
The nomenclature of alchemy is rich in description, but does not effectively meet the
aims outlined above. Opinions differ whether this was deliberate on the part of the early
practitioners of alchemy or whether it was a consequence of the particular (and often
esoteric) theoretical framework in which they worked.
While both explanations are probably valid to some extent, it is remarkable that the first
"modern" system of chemical nomenclature appeared at the same time as the distinction
(by Lavoisier) between elements and compounds, in the late eighteenth century.
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The French chemist Louis-Bernard Guyton de Morveau published his recommendations
in 1782, hoping that his "constant method of denomination" would "help the intelligence
and relieve the memory". The system was refined in collaboration with Berthollet, de
Fourcroy and Lavoisier, and promoted by the latter in a textbook which would survive
long after his death at the guillotine in 1794. The project was also espoused by Jöns
Jakob Berzelius, who adapted the ideas for the German-speaking world.
The recommendations of Guyton covered only what would be today known as inorganic
compounds. With the massive expansion of organic chemistry in the mid-nineteenth
century and the greater understanding of the structure of organic compounds, the need for
a less ad hoc system of nomenclature was felt just as the theoretical tools became
available to make this possible. An international conference was convened in Geneva in
1892 by the national chemical societies, from which the first widely accepted proposals
for standardization arose.
A commission was set up in 1913 by the Council of the International Association of
Chemical Societies, but its work was interrupted by World War I. After the war, the task
passed to the newly formed International Union of Pure and Applied Chemistry, which
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first appointed commissions for organic, inorganic and biochemical nomenclature in
1921 and continues to do so to this day.
Types of nomenclature
Organic chemistry
• Substitutive name
• Functional class name, also known as a radicofunctional name
• Conjunctive name
• Additive name
• Subtractive name
• Multiplicative name
• Fusion name
• Hantzsch–Widman name
• Replacement name
Inorganic chemistry
Compositional nomenclature
Examples of compositional names are:
• PCl5 phosphorus pentachloride
• N2O4 dinitrogen tetraoxide
An alternative method uses the oxidation state on the metal in place of suffices, e.g.:
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• SnCl2, tin(II) chloride as an alternative to tin dichloride.
Generally this system, known as Stock nomenclature or international nomenclature, is
preferred over the prefix system for ionic compounds.
Substitutive nomenclature
This naming method generally follows established IUPAC organic nomenclature.
Hydrides of the main group elements (groups 13–17) are given -ane base names, e.g.
borane (BH ), oxidane (H O), phosphane (PH ) (the name phosphine is also in common
3 2 3
use, but is not recommended by IUPAC). The compound PCl would be named
3
substitutively as trichlorophosphane.
Additive nomenclature
This naming method has been developed principally for coordination compounds
although it can be more widely applied. An example of its application is:
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• [CoCl(NH3)5]Cl2 pentaamminechloridocobalt(III) chloride
Note that ligands such as chloride become chlorido- rather than chloro- as in substitutive
naming.
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Chapter- 2
IUPAC Nomenclature of Inorganic Chemistry

The IUPAC nomenclature of inorganic chemistry is a systematic method of naming
inorganic chemical compounds, as recommended by the International Union of Pure and
Applied Chemistry (IUPAC). The rules are commonly known as "The Red Book" Ideally,
every inorganic compound should have a name from which an unambiguous formula can
be determined. There is also an IUPAC nomenclature of organic chemistry.
System
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The names "caffeine" and "3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione" both
signify the same chemical. The systematic name encodes the structure and composition
of the caffeine molecule in some detail, and provides an unambiguous reference to this
compound, whereas the name "caffeine" just names it. These advantages make the
systematic name far superior to the common name when absolute clarity and precision
are required. However, for the sake of brevity, even professional chemists will use the
non-systematic name almost all of the time, because caffeine is a well-known common
chemical with a unique structure. Similarly, H O is most often simply called water in
2
English, though other chemical names do exist.
1. Single atom anions are named with an -ide suffix: for example, H− is hydride.
2. Compounds with a positive ion (cation), the name of the compound is simply the
cation's name (usually the same as the element's), followed by the anion. For
example, NaCl is sodium chloride, and CaF is calcium fluoride.
2
3. Cations able to take on more than one positive charge are labeled with Roman
numerals in parentheses. For example, Cu+ is copper(I), Cu2+ is copper(II). An
older, deprecated notation is to append -ous or -ic to the root of the Latin name to
name ions with a lesser or greater charge. Under this naming convention, Cu+ is
cuprous and Cu2+ is cupric.
4. Oxyanions (polyatomic anions containing oxygen) are named with -ite or -ate, for
a lesser or greater quantity of oxygen. For example, NO − is nitrite, while NO − is
2 3
nitrate. If four oxyanions are possible, the prefixes hypo- and per- are used:
hypochlorite is ClO−, perchlorate is ClO −,
4
5. The prefix bi- is a deprecated way of indicating the presence of a single hydrogen
ion, as in "sodium bicarbonate" (NaHCO ). The modern method specifically
3
names the hydrogen atom. Thus, NaHCO would be pronounced "sodium
3
bicarbonate".
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Positively charged ions are called cations and negatively charged ions are called anions.
The cation is always named first. Ions can be metals or polyatomic ions. Therefore the
name of the metal or positive polyatomic ion is followed by the name of the non-metal or
negative polyatomic ion. The positive ion retains its element name whereas for a single
non-metal anion the ending is changed to -ide.
Example: sodium chloride, potassium oxide, or calcium carbonate.
When the metal has more than one possible ionic charge or oxidation number the name
becomes ambiguous. In these cases the oxidation number (the same as the charge) of the
metal ion is represented by a Roman numeral in parentheses immediately following the
metal ion name. For example in uranium(VI) fluoride the oxidation number of uranium is
6. Another example is the iron oxides. FeO is iron(II) oxide and Fe O is iron(III) oxide.
2 3
An older system used prefixes and suffixes to indicate the oxidation number, according to
the following scheme:
Oxidation state Cations and acids Anions
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Lowest hypo- -ous hypo- -ite
-ous -ite
-ic -ate
per- -ic per- -ate
Highest hyper- -ic hyper- -ate
Thus the four oxyacids of chlorine are called hypochlorous acid (HOCl), chlorous acid
(HOClO), chloric acid (HOClO ) and perchloric acid (HOClO ), and their respective
2 3
conjugate bases are the hypochlorite, chlorite, chlorate and perchlorate ions. This system
has partially fallen out of use, but survives in the common names of many chemical
compounds: the modern literature contains few references to "ferric chloride" (instead
calling it "iron(III) chloride"), but names like "potassium permanganate" (instead of
"potassium manganate(VII)") and "sulfuric acid" abound.
Traditional naming
Naming simple ionic compounds
An ionic compound is named by its cation followed by its anion.
For cations that take on multiple charges, the charge is written using Roman numerals in
parentheses immediately following the element name) For example, Cu(NO ) is
3 2
copper(II) nitrate, because the charge of two nitrate ions (NO -1) is 2 × −1 = −2, and
3
since the net charge of the ionic compound must be zero, the Cu ion has a 2+ charge. This
compound is therefore copper(II) nitrate. In the case of cations with a 4+ oxidation state,
the acceptable format for the Roman numeral 4 is IV and not IIII.
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