In describing chemical substances, we are dealing with a need for effective communication using as appropriate language. In a sense chemical nomenclature is as much a language as is Greek or Mandarin, albeit a restricted one with a very specific purpose; it has an organizational structure. "rules of grammar", conventions and undergoes continuous evolution.
Chemical nomenclature may be considered to be a language. As such, it is made up of words, and it should obey the rules of syntax. Generally, nomenclature systems use a base on which the name is constructed. This base can be derived from a parent compound name in substitutive nomenclature or from a central atom name such as cobalt in additive nomenclature.
Define NomenclatureBack to Top
The name of a chemical compound usually contains information about its molecular composition. The naming of things or choosing the names of compounds especially in science or chemistry called nomenclature of chemical compounds.
Binomial Nomenclature Definition
Binomial nomenclature is the scientific method of giving names to all the organisms so that they can be easily distinguished from one another. It is the system of nomenclature using two terms, the first one indicating the genus and the second the species.
Binomial nomenclature examples are the mango tree is scientifically known as Mangnifera indica.
Nomenclature RulesBack to Top
The rules for naming the chemical compound is also based on the type of the compound. A set of rules given below to name a chemical compound.
- Name the first element using the exact element name.
- Name the second element by writing the stem name of the element with the suffix -ide.
- Add prefixes to each element name to denote the subscript of the element in the formula. Generally the prefix mono is used only on the second element in the binary compound to distinguish from other examples containing multiple atoms.
- For metals that can have more than one stable charge, report the charge as part of the name. Write the charge in roman numeral form in parentheses immediately after the metals name.
Chemical Nomenclature ChartBack to Top
||Fatty acid nomenclature||CH3(CH2)nCOOH
||Amine nomenclature||R-NH2, R-NH-R', R'-NR-R"||
||Carboxylic acid nomenclature||
|The IUPAC nomenclature of carboxylic acid have ac -oic acid suffix. In common nomenclature the suffix is usually -ic acid. For example, stearic acid and octadecanoic acid.
|6||Alcohol nomenclature||CnH2n+1OH ||Alcohol nomenclature follow these steps.|
|7 ||Benzene nomenclature||C6H6|
|8 ||Enzyme nomenclature||ES (E = enzyme, S = substrate)|
|9 ||Aldehyde nomenclature||RCHO||The IUPAC system aldehydes are named by replacing "e" from the corresponding name of alkane by suffix "al". Therefore aldehydes are called alkanals.|
|10 ||Ketone nomenclature||R||The name of the ketone is obtained by replacing "e" of the parent alkane by "one". The positions of the carbonyl group and substituents are indicated by numbers.|
|11 ||Amide nomenclature||RC(O)NHR' |
|12||Oxyanions||AxOyz− (A = chemical element and O = oxygen)||Oxyanions are named with -its or -ate, for a leaser or greater quantity of oxygen.|
Alkane NomenclatureBack to Top
- Choose the longest carbon chain and name this.
- Name all groups which are attached to the longest chain as alkyl groups.
- Number the longest carbon chain beginning at the end that is closest to an alkyl group.
- Write the name of the alkane by naming all the substituent first in alphabetical order, followed by alkane name for the longest carbon chain in the compound.
The IUPAC rules for naming cycloalkanes are as follows.
- The name of an unsubstituted cycloalkane is obtained by attaching the prefix cyclo- to the name of the corresponding normal alkane having the same number of carbon atoms as in the ring.
- Substituents on the ring are named and numbers indicate their positions. The ring is numbered so that the carbons bearing the substituents will have the lowest numbers.
Naming Branched Alkanes
The key to naming branched alkanes is knowing the name of the branch or branches that are attached to the main carbon chain. These branches are formally called substituents. A substituent is an atom or group of atoms attached to a chain of carbon atoms. For branched chain alkanes, the substituents are specifically called alkyl groups.
- Determine the longest continuous carbon chain that contains the double bond, and name it with the appropriate root and the suffix -ene.
- Assign the first carbon atom of the double bond the lowest possible number.
- Name substituent branches as alkyl groups with their positions indicated by numbers.
- Indicate multiple substituents with the appropriate Greek prefix.
Alkyne NomenclatureBack to Top
- Locate the parent chain.
- Number the chain to give the alkyne the lowest possible number.
- Name the substituents.
- Place the substituents in alphabetical order in front of the parent name.
Inorganic NomenclatureBack to Top
Naming inorganic compounds is usually quite straightforward because small numbers of atoms are involved. Inorganic compounds are classified into four categories in order to simplify the nomenclature.
- Ionic compounds
- Molecular compounds
- Acids and bases
Hydrates are ionic compounds that have absorbed water. They are named as the ionic compound followed by a numerical prefix and -hydrate. For example, CuSO4.5H2O is named as copper (II) sulfate pentahydrate.
Nomenclature PracticeBack to Top
- The parent acid for this amide is butyric acid (common) or butanoic acid (IUPAC). The common name for this amide is butyramide and the IUPAC name is butanamide.
- In both the common and IUPAC system of nomenclature the name of the parent acid is the same benzoic acid. The name of the amide is N,N-diphenylbenzamide.
- This is something we draw on board. Thia is the hood ornament of a Mercedes, so this is Mercedes Benzene.
- The highest priority functional group is the alcohol. The longest chain contain the OH is nine, so it is a nonenol of some sort. Numbering from the right to give the OH the lower number gives us 1-methoxy-5-phenylnon-8-en-2-ol.