In chemical nomenclature, 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). It is published in Nomenclature of Inorganic Chemistry (which is informally called 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.
1 System 2 Traditional naming
2.1 Naming simple ionic compounds
2.1.1 List of common ion names
2.2 Naming hydrates 2.3 Naming molecular compounds
2.3.1 Common exceptions
3 2005 revision of IUPAC's nomenclature for inorganic compounds 4 Nomenclature of Inorganic Chemistry 5 See also 6 References 7 External links
System 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, H2O is most often simply called water in English, though other chemical names do exist.
Single atom anions are named with an -ide suffix: for example, H− is
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 CaF2 is
Cations which have taken on more than one positive charge are labeled
Positively charged ions are called cations and negatively charged ions are called anions. The cation is always named first. Ions can be metals, non-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 Fe2O3 is iron(III) oxide. An older system used prefixes and suffixes to indicate the oxidation number, according to the following scheme:
Oxidation state Cations and acids Anions
Lowest hypo- -ous hypo- -ite
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 (HOClO2) and perchloric
acid (HOClO3), and their respective 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.
Naming simple ionic compounds
An ionic compound is named by its cation followed by its anion. See
polyatomic ion for a list of possible ions.
For cations that take on multiple charges, the charge is written using
Cl− chloride S2− sulfide P3− phosphide
NH+ 4 ammonium H 3O+ hydronium NO− 3 nitrate NO− 2 nitrite ClO− hypochlorite ClO− 2 chlorite ClO− 3 chlorate ClO− 4 perchlorate SO2− 3 sulfite SO2− 4 sulfate HSO− 3 hydrogen sulfite (or bisulfite) HCO− 3 hydrogen carbonate (or bicarbonate) CO2− 3 carbonate PO3− 4 phosphate HPO2− 4 hydrogen phosphate H 2PO− 4 dihydrogen phosphate CrO2− 4 chromate Cr 2O2− 7 dichromate BO3− 3 borate AsO3− 4 arsenate C 2O2− 4 oxalate CN− cyanide SCN− thiocyanate MnO− 4 permanganate
Naming hydrates Hydrates are ionic compounds that have absorbed water. They are named as the ionic compound followed by a numerical prefix and -hydrate. The numerical prefixes used are listed below (see IUPAC numerical multiplier):
mono- di- tri- tetra- penta- hexa- hepta- octa- nona- deca-
For example, CuSO4·5H2O is "copper(II) sulfate pentahydrate". Naming molecular compounds Inorganic molecular compounds are named with a prefix (see list above) before each element. The more electronegative element is written last and with an -ide suffix. For example, H2O (water) can be called dihydrogen monoxide. Organic molecules do not follow this rule. In addition, the prefix mono- is not used with the first element; for example, SO2 is sulfur dioxide, not "monosulfur dioxide". Sometimes prefixes are shortened when the ending vowel of the prefix "conflicts" with a starting vowel in the compound. This makes the name easier to pronounce; for example, CO is "carbon monoxide" (as opposed to "monooxide"). Common exceptions There are a number of exceptions and special cases that violate the above rules. Sometimes the prefix is left off of the initial atom: I2O5 is known as iodine pentoxide, but it should be called diiodine pentoxide. N2O3 is called nitrogen sesquioxide (sesqui- means 1 1⁄2). The main oxide of phosphorus is called phosphorus pentoxide. It should actually be diphosphorus pentoxide, but it is assumed that there are two phosphorus atoms (P2O5), as they are needed in order to balance the oxidation numbers of the five oxygen atoms. However, people have known for years that the real form of the molecule is P4O10, not P2O5, yet it is not normally called tetraphosphorus decaoxide. In writing formulas, ammonia is NH3 even though nitrogen is more electronegative. Likewise, methane is written as CH4 even though carbon is more electronegative. 2005 revision of IUPAC's nomenclature for inorganic compounds Main article: IUPAC nomenclature of inorganic chemistry 2005 Nomenclature of Inorganic Chemistry
The front cover of the 2005 edition of the Red Book
Nomenclature of Inorganic Chemistry, by chemists commonly referred to as the Red Book, is a collection of recommendations on IUPAC nomenclature, published at irregular intervals by the IUPAC. The last full edition was published in 2005, in both paper and electronic versions.
Release year Title Publisher ISBN
2005 Recommendations 2005 (Red Book) RSC Publishing 0-85404-438-8
2001 Recommendations 2000 (Red Book II) (supplement) RSC Publishing 0-85404-487-6
1990 Recommendations 1990 (Red Book I) Blackwell 0-632-02494-1
1971 Definitive Rules 1970  Butterworth 0-408-70168-4
1959 1957 Rules Butterworth
1940/1941 1940 Rules Scientific journals
IUPAC nomenclature of organic chemistry
List of inorganic compounds
^ Nomenclature of
Inorganic Chemistry IUPAC Recommendations 2005 -
Full text (PDF)
2004 version with separate chapters as pdf: IUPAC Provisional
Recommendations for the Nomenclature of
Inorganic Chemistry (2004)
Archived 2008-02-19 at the Wayback Machine.
International Union of Pure and Applied Chemistry
Bibliography of IUPAC Recommendations on Inorganic Nomenclature (last updated 17 February 2004) ChemTeam Highschool Tutorial PDF file SUNY Potsdam.edu American Chemical Society, Committee on Nomenclature, Terminology & Symbols Online version (2005 Recommendations) Recommendations 2000-Red Book II (incomplete) Definitive Rules 1970 (pdf) Official site IUPAC Nomenclature Books Series (commonly known as the "Colour Books") Bibliograp