Prefix numerical

Double bonds m the mam chain are signaled by the ending enow acid and their position IS designated by a numerical prefix Entries 6 and 7 are representative carboxylic acids that contain double bonds Double bond stereochemistry is specified by using either the cis-trans or the E-Z notation... 

Stoichiometric Proportions. The stoichiometric proportions of the constituents in a formula may be denoted by Greek numerical prefixes mono-, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona- (Latin), deca-, undeca- (Latin), dodeca-,. . . , icosa- (20), henicosa- (21),. . . , tri-conta-(30), tetraconta-(40),. . . , hecta-(100), and so on, preceding without a hyphen the names of the elements to which they refer. The prefix mono can usually be omitted occasionally hemi-(1/2) and sesqui- (%) are used. No elisions are made when using numerical prefixes except in the case of icosa- when the letter i is elided in docosa- and tricosa-. Beyond 10, prefixes may be replaced by Arabic numerals. 

Composite numeral prefixes are built up by citing units first, then tens, then hundreds, and so on. For example, 43 is written tritetraconta- (or tritetracontakis-). 

In indexing it may be convenient to italicize a numerical prefix at the beginning of the name and connect it to the rest of the name with a hyphen e.g., di-nitrogen pentaoxide (indexed under the letter n ). 

Isopolyanions. Isopolyanions are named by indicating with numerical prefixes the number of atoms of the characteristic element. It is not necessary to give the number of oxygen atoms when the charge of the anion or the number of cations is indicated. 

Table 1 lists some of the common binucleophiles utilized in heterocyclic synthesis, the numerical prefixes referring to the relative positions of the nucleophilic centers to each other. Higher order binucleophiles, e.g. 1,5-systems, come readily to mind and the above illustrative examples rapidly increase in scope when the incorporation of these structural elements into heterocyclic systems is considered. This last group offers many opportunities for ring annulations. 

Begin numbering the branched substituent at its point of its attachment to the main chain, and identify it as a 2-methylpropyl group. The substituent is alphabetized according to the first letter of its complete name, including any numerical prefix, and is set off in parentheses when naming the entire molecule. 

Verify that the numerical prefixes give the correct total number of ligands, that the ligands are named alphabetically, and that the overall species is charge-neutral. 

Numerical Prefixes Commonly Used in Forming Chemical Names... 

Numeral Prefix Numeral Prefix Numeral Prefix... 

Molecular orbitals are sometimes given numerical prefixes to show the order in which the orbitals having those type and symmetry designations are encountered. When this is done, the order of filling the molecular orbitals for the second-row elements is shown as... 

Nomenclature based on a parent term with an appended suffix accounts for most natural product names. However, as related compounds are identified, or even when a suffix has to denote multiple functional groups, a variety of modifying terms can be employed. For example, the common prefix nor- denotes the removal of a skeletal atom from the parent structure the loss of two or more skeletal atoms is indicated by combining an appropriate numerical prefix with nor- , e.g., dinor- , trinor- (Giles 1999). Table 1.2 lists additional examples of commonly encountered modifying terms. 

Chemical name Numerical prefix Molecular formula Number of isomers... 

Graft copolymers with known numbers of graft chains are named using numeric prefixes (mono, bis, tris, etc). 

Numerical prefixes (placed before a name, but joined to it by a hyphen), infixes (inserted into a name, usually between hyphens) and suffixes (placed after a name). 

Of the two kinds of numerical prefix (see Table 4.2), the simple di-, tri-, tetra-, etc. are generally recommended. The prefixes bis-, tris-, tetrakis-, etc. are to be used only with more complex expressions and to avoid ambiguity. They normally require parentheses around the name they qualify. The nesting order of enclosing marks is as cited on p. 13. There is normally no elision in instances such as tetraammine and the two adjacent letters a are pronounced separately. 

A. 2 . The prefixes in the name indicate the compound is molecular, so you don t need to worry about ionic charges. Just identify the element and the number of atoms based on the numerical prefix and then write it down. In this case, you have two carbons indicated by the di- and four hydrogens indicated by the tetra-... 

The use of numerical prefixes to distinguish between orbitals of the same symmetry was suggested by Mulliken and is the generally accepted method. The prefixes may be omitted when it is clear that no ambiguity is present. 

In the discussion of the bonding of the E2 molecules in the next section, the orbitals are referred to by their symmetry symbols with the appropriate numerical prefixes. 

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