Naming compounds number prefixes used

In all common names for ionic compounds, number prefixes are not used to... 

In the case where two or more different. substituents are present, the substituent names are alphabetized in the systematic name of the compound. Numbers are used to indicate the positions of the alphabetized substituents. If a prefix is used to denote two or more identical substituents, the prefix is not used to determine the alphabetization—only the substituent name is used. 

The number of carbon atoms and the type of bond that form the name of a carbon compound is shown using the prefixes and suffixes in Table 3.2. 

The names of the alkenes are formed with the same prefixes used in naming the alkanes. These prefixes correspond to the number of carbon atoms in the compound. The suffix is -ene, which indicates that the compound belongs to the alkene family. Thus the simplest member of the alkene family, C2H4, should be called ethene. Ethene is commonly known as ethylene, Figure 1-8. The next larger member of the family, propene, commonly is called propylene. 

The procedure for naming a compound involves some or all of the following steps, depending on the structure of the molecule under study (1) the type of nomenclature to be used (conjunctive, multiplicative, etc.) is chosen (2) the parent structure is named (3) the prefixes, suffixes, and names of funcUonal and substituent groups that were not included in (2) me attached (4) the numbering is completed. 

Aromatic acids of the form Ar—COOH are named as derivatives of benzoic acid, Ph—COOH. As with other aromatic compounds, the prefixes ortho-, meta-, and para-may be used to give the positions of additional substituents. Numbers are used if there are more than two substituents on the aromatic ring. Many aromatic acids have historical names that are unrelated to their structures. 

To indicate that a binary compound is made up of two non-metals, a prefix is usually added to both non-metals in the compound. This prefix indicates the number of atoms of each element in one molecule or formula unit of the compound. For example, P205 is named diphosphorus pen-toxide. Alternatively, the Stock System may be used, and P205 can be named phosphorus (V) oxide. AsBr3 is named phosphorus tribromide. 

Both common and systematic names of compounds are used throughout this volume, depending on which the Editor-in-Chief felt was more appropriate. Preparations appear in alphabetical order of titles of the synthetic procedures. The Chemical Abstracts indexing name for each title compound, if it differs from the title name, is given as a subtitle. Systematic Chemical Abstracts nomenclature, used in both the 8th and 9th Collective Indexes for the title compound and a selection of other compounds mentioned in the procedure, is provided in an appendix at the end of each preparation. Registry numbers, which are useful in computer searching and identification, are also provided in these appendixes. Whenever two names are concurrently in use and one name is the correct Chemical Abstracts name, that name is adopted. For example, both diethyl ether and ethyl ether are normally used. Since ethyl ether is the established Chemical Abstracts name for the 8th Collective Index, it has been used in this volume. The 9th Collective Index name is 1, l -oxybisethane, which the Editors consider too cumbersome. The prefix -is deleted from M-alkanes and n-alkyls. All reported dimensions are now expressed in Systeme International units. 

Covalent Compounds The names of covalent compounds differ from those of ionic compounds in that covalent compounds require the use of a prefix to indicate the number of atoms present. Examples are CO carbon monoxide and C02 carbon dioxide. Other prefixes that can be used are tri- and tetra-. 

Name the compound, remembering to use the prefix "tri-" before "methyl" and remembering to use a number to signify the location of the double bond. The name of the compound in (a) is 3,4,4-trimethyl-1 -pentene. 

In Chap. 6 we placed Roman numerals at the ends of names of metals to distinguish the charges on monatomic cations. It is really the oxidation number that is in parentheses. This nomenclature system is called the Stock system. For monatomic ions, the oxidation number is equal to the charge. For other cations, again the oxidation number is used in the name. For example, Hg2 + is named mercury(I) ion. Its charge is 24- the oxidation number of each atom is 4-1. Oxidation numbers are also used for other cations, such as dioxovanadium(V) ion, V02". The prefix 0x0- stands for oxygen. Oxidation numbers can be used with nonmetal-nonmetal compounds, as in sulfur(VI) oxide for SO3, but the older system using prefixes (Table 6-2) is still used more often. 

The rules for naming binary compounds are summarized in Fig. 2.22. Notice that prefixes to indicate the number of atoms are used only in Type III binary compounds (those containing two nonmetals). An overall strategy for naming compounds is summarized in Fig. 2.23. 

Compounds with two hydroxy groups are called diols (using the lUPAC system) or glycols. Compounds with three hydroxy groups are called triols, and so forth. To name a diol, for example, the suffix -diol is added to the name of the parent alkane, and numbers are used in the prefix to indicate the location of the two OH groups. 

The central atom names are listed after the ligand names. The multiplicative prefix di is used where the central atoms are the same element. Otherwise, the order of the central atom names is obtained using Table VI. The order of the central atom names is reflected in the numbering employed with the K symbols. The ending ate is added if the dinuclear compound is an anion, and a radical dot may be added for radicals. In the case of two different central atoms, the two names are cited inside parentheses and ate is added outside the parentheses. 

For binary molecular compounds (compounds with only two elements), the name begins with the name of the element that is farthest to the left and lowest in the periodic table. The name of the second element is given the suffix -ide and a Greek number prefix is used on the first element if necessary (e.g., dinitrogen tetroxide, N204). 

Some systematic method for naming compounds is necessary. The system in use today is prescribed by the International Union of Pure and Applied Chemistry (TUPAC). The names of the first 20 straight-chain alkanes are listed in Table 27-2. You should become familiar with at least the first ten. The names of the alkanes starting with pentane have prefixes (from Greek) that give the number of carbon atoms in the molecules. All alkane names have the -ane ending. 

Binary compounds with two nonmetals are named with the element to the left or below in the periodic table named first. The other element is then named, with its ending changed to -ide and a prefix added to denote the number of atoms of that element present. If there is more than one atom of the first element present, a prefix is used with the first element also. If one of the elements is to the left and the other below, the one to the left is named first unless that element is oxygen or fluorine, in which case it is named last. The same order of elements is used in writing fomiulas for these compounds. The element with the lower electronegativity is usually named first. The prefixes are listed in Table 5.1. 

The relative positions of two substituents on a benzene ring can be indicated either by numbers or by the prefixes ortho, meta, and para. Adjacent substituents are called ortho, substituents separated by one carbon are called meta, and substituents located opposite one another are designatedpara. Often, only their abbreviations (o, m,p) are used in naming compounds. 

A carbon chain can also have more than one hydroxyl group. To name these compounds, prefixes such as di-, tri-, and tetra- are used before the -ol to indicate the number of hydroxyl groups present. The full alkane name, including -ane, is used before the prefix. 

Some compounds of alkenes have more than one double bond in the structure. Naming of the prefix for the number of carbons is the same as with the other alkenes. The ending ene is still used to indicate double bonds in the alkene family. There is, however, a prefix used to indicate the number of double bonds in the compound. The prefix di is inserted before the ene in the name to indicate two double bonds. For example, butene with two double bonds is called butadiene. The prefix tri is inserted to indicate three double bonds. Hexene, with three double bonds, is called hexatriene. There must be at least four carbons before two double bonds can... 

Substitutive nomenclature (Section 4.3F) A system for naming compounds in which each atom or group, called a substituent, is cited as a prefix or suffix to a parent compound. In the lUPAC system only one group may be cited as a suffix. Locants (usually numbers) are used to tell where the group occurs. 

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