Hepta- prefix

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. 

Numbers of ligands are indicated by Greek prefixes di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona- (ennea-), deca-, etc. If, however, the names of the ligands themselves already contain these prefixes (e.g., diethyl-enefnamine), the ligand name is placed in parentheses and the prefix outside becomes bis-, tris-, tetrakis-, pentakis-, hexakis-, etc. 

Indicate how many of each element is present with a prefix multiplier (mono = 1 di = 2 tri = 3 tetra = 4 penta = 5 hexa = 6 hepta = 7 octa = 8)... 

Prefix mono- di- tri- tetra- penta- hexa- hepta- octa- nona- deca-... 

Table C Metric Multipliers tera, peta, exa come from tetra, penta, hexa with one letter removed zetta, yotta come from zeta, iota, with one letter added atto comes from Danish "atten" for 18 zepto comes from Latin "septem" or Greek "hepta" (1000 7) and yocto comes from Greek "octo" (1000-8) with one prefix letter added...

The systematic nomenclature for the cycloproparenes is confused because the fusion rule (lUPAC Rule A 21.3) requires that at least two rings of five or more members be present before the prefix cyclopropa may be used. Thus while l//-cyclopropa[a]- and -[ Jnaphthalene are correct for 10 and 11, respectively, li/-cyclopropabenzene is incorrect for 1. The Chemical Abstracts service and lUPAC are unanimous in naming 1 as bicyclo-[4.1.0]hepta-l,3,5-triene la. Thus if the parent member is strictly named, not only does it differ from that of its higher homologues, but also it could be taken to imply a bond localized structure. Throughout this chapter parent 1 and its derivatives 5-9 are referred to as cyclopropabenzenes and numbered as shown for structure 1. 

Because the molecule has a seven-carbon chain, you use the prefix hepta-. Because it has two double bonds, you use the prefix di- before -ene, giving the name heptadiene. Adding the numbers 2 and 4 to designate the positions of the double bonds, you arrive at the name 2,4-heptadiene. 

Nearly all binary molecular compormds involve two nonmetals bonded together. Although many nonmetals can exhibit different oxidation numbers, their oxidation numbers are not properly indicated by Roman numerals or suffixes. Instead, elemental proportions in binary covalent compounds are indicated by using a prefix system for both elements. The Greek and Latin prefixes for one through ten are mono, di, tri, tetra, penta, hexa, hepta, octa, nona, and deca. The prefix mono- is omitted for both elements except in the common name for CO, carbon monoxide. We use the minimum number of prefixes needed to name a compound unambiguously. The final a in a prefix is omitted when the nonmetal stem begins with the letter o we write heptoxide, not heptaoxide. ... 

To see how this process works, examine how structure (f) was written. The parent name is heptadiene. The prefix "hepta" indicates that seven carbons are present in the skeleton C-C-C-C-C-C-C. The 2,3 indicates the positions of the two double bonds - it is a diene. So, one can write C-C=C=C-C-C-C. With this numbering system, the 1 2 3 4 5 6 7... 

The prefixes used in the names of these hydrates are mono- (one), di- (two), tri- (three), tetra- (four), penta- (five), hexa- (six), hepta- (seven) etc. 

The first element is named first, using the unchanged element name sulfur. The second element s root is then written with the suffix -ide. ox- plus -ide = oxide. There are two sulfur atoms, so the prefix di-is added. There are seven oxygen atoms, so the prefix hepta- is added. Thus, the complete name is disulfur heptoxide. (The a in hepta- is dropped before the vowel o in oxide.)... 

Returning to the simple alkanes, the names from pentane onwards derive from the number of carbon atoms. For now, we ll just look at the linear alkanes, and the names are shown in Table 2.2. Each name is composed of a root, which tells us how many carbon atoms we have, plus a suffix, which tells us what type of molecule it is. For alkanes, our suffix is -ane. Most of the prefixes are Greek in origin, and many will be familiar from other words that you know. You would not easily deduce the names of very long alkanes, but most will be understandable, once seen. For example, C74H150 is tetraheptacontane tetra- gives us the 4 and hepta- the 7, and contane is used for the decades between 30 and 100. 

Some pairs of nonmetals form more than one binary molecular compound, and we need to distinguish among them. Generally, we indicate relative numbers of atoms through prefixes mono =, di = 2, tri = 3, tetra = 4, penta = 5, hexa = 6, hepta = 7, octa = 8, nona = 9, deca = 10, and so on. Thus, for the two principal oxides of sulfur we write... 

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