Greek names prefixes

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. 

Traditionally, carotenoids have been given trivial names derived usually from the biological source from which they are isolated, but a semisystematic scheme has been devised that allows carotenoids to be named unambiguously and in a way that defines and describes their structure (Table 7.2). Specific names are based on the stem name carotene preceded by the Greek-letter prefixes that designate the two end groups. For example, 3-carotene is correctly referred to as p, p-carotene, and a-carotene as p, e-carotene. 

Names.—The names of the different hydrocarbons are similar and are in harmony with the idea of an homologous series. The common termination ane is given to all and, above the fourth member, a Greek numerical prefix indicates the number of carbon atoms in the molecule. The five-carbon compound is pent-ane, the six carbon hex-ane, etc. The first four members have special non-numerical prefixes as methane, eth-ane, prop-ane and but-ane. Similarly the radicals of each hydrocarbon simply take the termination yl in place of ane, thus, but-yl, pent-yl, hex-yl, etc. 

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). 

Since the I.U.C. rules and the Chemical Abstracts indexes do not provide any assistance in naming carbonyls and nitrosyls, the names used in the literature, in which Greek numerical prefixes are used, have been retained e.g.,... 

Covalent compounds use Greek numerical prefixes (see Table 2.6) to indicate the number of atoms of each element. The first element in the name has a prefix only when more than one atom of it is present the second element usually has a prefix. 

The lUPAC rules assign names to unbranched alkanes as shown m Table 2 2 Methane ethane propane and butane are retained for CH4 CH3CH3 CH3CH2CH3 and CH3CH2CH2CH3 respectively Thereafter the number of carbon atoms m the chain is specified by a Latin or Greek prefix preceding the suffix ane which identifies the com pound as a member of the alkane family Notice that the prefix n is not part of the lUPAC system The lUPAC name for CH3CH2CH2CH3 is butane not n butane... 

When side chains of two or more different kinds are attached to a cyclic component, only the senior side chain is named by the conjunctive method. The remaining side chains are named as prefixes. Likewise, when there is a choice of cyclic component, the senior is chosen. Benzene derivatives may be named by the conjunctive method only when two or more identical side chains are present. Trivial names for oxo carboxylic acids may be used for the acyclic component. If the cyclic and acyclic components are joined by a double bond, the locants of this bond are placed as superscripts to a Greek capital delta that is inserted between the two names. The locant for the cyclic component precedes that for the acyclic component, e.g., indene-A - -acetic acid. 

The system for naming the straight-chain hydrocarbons is based on an agreed-upon method of retaining the first three or four common names, then using Greek prefixes that indicate the number of carbon atoms in the chain. For isomers, the same system is used, always using the name of the compound that is attached to the chain and the name of the chain. 

The first word gives the name of the element that appears first in the formula a Greek prefix (Table 2.4) is used to show the number of atoms of that element in the formula. 

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