Nona- 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. 

For monocyclic prefixes other than benzo , the following names are recognized, each to represent the form with the maximum number of non-cumulative double bonds cyclopenta, cyclohepta, cycloocta, cyclo-nona, etc. When the base component is a monocyclic system, the ending -ene signifies the maximum number of non-cumulative double bonds, and thus does not denote one double bond only. 

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

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. ... 

The name of a borane denotes the number of boron atoms, the number of hydrogen atoms, and the overall charge. The number of boron atoms is given by a Greek prefix (di-, tri-, tetra-, penta-, hexa- etc.), the exception being for nine and eleven, where the Latin nona- and undeca- are used. The number of hydrogen atoms is shown as an Arabic numeral in parentheses at the end of the name (see below). The charge for an ion is shown at the end of the name the nomenclature... 

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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