Chemical names accepted structural prefixes

Use italic type for positional, stereochemical, configurational, and descriptive structural prefixes when they appear with the chemical name or formula. Use a hyphen to separate them from the chemical name. Accepted prefixes include the following ... 

The lists of regulated dangerous goods in transportation include many chemical prefixes that codify the structure of molecules, usually organic. Over time, many conventions have arisen that result in the acceptance of today s somewhat inconsistent scheme. On occasion, these prefixes may be placed in the centre of a chemical name, preceding a functional group or atom, or, very rarely, at the end of a name. 

A new, fully developed nomenclature system was published in 1984 by the Japanese chemist Hirayama. The system known under the name HIRN contains many novel ideas and is accepted as an important development in the field of chemical nomenclature. The approach is to use a nodal configuration for acyclic and some cyclic structures, and a system based on the arrangement of six-membered rings for aromatic compounds and related structures. This latter approach is then extended to cover other ring sizes by use of prefixes denoting reduction and enlargement of the ring size. 

As a result of chemical, optical, thermal, and X-ray studies of chromium-bearing chlorites, Lapham suggested a definitive classification based on the structural location of Cr. He showed that for Cr203 contents under 2%, there is no noticeable effect of Cr on the structure. He suggested using the accepted Mg-Fe chlorite classification with a Cr prefix for these specimens, for example, Cr-clinochlore or Cr-penninite. For CrjOj contents greater than 2 %, there are appreciable effects on the optical, thermal, and X-ray properties. These effects differ, depending on whether the Cr is present in tetrahedral or octahedral coordination. Lapham recommends use of the name kammererite for specimens with octahedral Cr, and the name kotschubeite for those with tetrahedral Cr. 

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