INDEX-ENTRY

REF ONLY( CLASS( REAL, INTEGER, GEOMETRIC, ASPECT, FACE, PLACEMENT, MACRO, ROUTINE, RECORD TYPE) )  

Entities of the classes specified in the schema may have a user-defined name associated. This user-defined name may be used to identify the entities whenever an interactive identification (by picking on the workstation monitor) is not possible. In particular, when sequences of commands to the CAD system are input on the keyboard or read from a text file, user-defined names serve for identifying entities. 

User-defined names must be unique in each scope. 

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When compounds of complex structure are considered, the number of name possibilities grows rapidly. To avoid having index entries for all possible names. Chemical Abstracts Service has developed what might be called the principle of inversion. The indexing system employs inverted... 

Indicator solutions a number of indicator solutions are listed in this section under the names of the indicators e.g., alizarin, aurin, azolitmin, et al., which follow alphabetically. See also various index entries. 

Coordinate Indexing and Boolean Logic. Three methods of indexing have been prominent in the chemical Hterature in recent times. The first, articulated indexing, has been used in printed Chemicaly hstracts subject indexes from their earliest days until well into the 1990s. A number of important concepts are identified as permissible index entries, including specific compounds, material types, reactions, and processes. One or more modifying statements foUow each basic index entry. Thus, eg. 

Because authors have approached similar topics from different viewpoints, index entries to those topics may appear under several headings. Thus a reader interested in, for example, the synthesis of acetyl-3Tf-azepin-2-ones should refer both to general entries (e.g. Azepinones, Azepin-2-ones, 3JT-Azepin-2-ones) and to specific entries (e.g. 3JT-Azepin-2-one, 3-acetyl- 3f7-Azepin-2-one, 7-acetyl-). 

Index entries are divided into two categories, primary and secondary. Primary index entries are used when a significant part of the text is devoted to a particular ring system this may be a whole chapter, or a section or subsection. Secondary index entries are used when a heterocyclic system is mentioned in a chapter devoted to another (primary) system. This may be, for example, as a starting material or as a product, or in a discussion comparing properties. 

By the procedure outlined above, all information regarding a specific compound that has been published up to about a year before the search can be found by a procedure that is always straightforward and that in many cases is rapid (if the compound has been reported only a few times). Equally important, if the compound has not been reported, the investigator will know that, too. It should be pointed out that for common compounds, such as benzene, ether, acetone, and so on, trivial mentions in the literature are not indexed (so they will not be found by this procedure), only significant ones. Thus, if acetone is converted to another compound, an index entry will be found, but not if it is used as a solvent or an eluant in a common procedure. 

The LI means that this is line one. Future answers from the system will number the lines in consecutive order. The 4 means that the system has four abstracts that contain the word semipinacol. The word may be in the title, an index entry, or a keyword. The search term may be the name of a compound, which means that individual compounds can be searched for in this way. If the name used is the CA indexing name, all the abstracts mentioning that compound will be retrieved. 

This means there are 42 entries that have the words AMBIDENT and NUCLEOPHILE somewhere in them in the titles, keywords, or index entries. We can now, if we wish, display any or all of them. But a particular entry might have these two words in unrelated contexts, for example, it might be a paper about ambident electrophiles, but which also has NUCLEOPHILE as an index term. We would presumably get fewer papers, but with a higher percentage of relevant ones, if we could ask for AMBIDENT NUCLEOPHILE, and in fact, the system does allow... 

The majority of the names for chemicals in this alphabetically arranged index conform to one of the systematic series permitted under various sections of the IUPAC Definitive Rules for Nomenclature. Where there is a marked difference between these names and the alternative names recommended in the IUPAC-based BS2472 1983 or ASE 1985 nomenclature lists, or long established traditional names, these are given as synonyms in parentheses after the main title. These synonyms also have their own index entry, cross-referenced back to the IUPAC-based names used as bold titles in the text of Volume 1. 

ORGANOSILYL PERCHLORATES PERCHLORATE-DOPED CONDUCTING POLYMERS PERCHLORATE SALTS OF NITROGENOUS BASES and the individually indexed entries ... 

Except for the peroxides individually listed below, all index entries have been assigned to the structurally based groups ... 

Individually indexed entries are t Chloroethylene, 0730 t 1,3-Cyclohexadiene, 2361 t Cyclopentadiene, Oxygen, 1857 t 1,1-Dichloroethylene, 0695 t Diethyl ether, 1697... 

It is the set of methods for representing, sorting, manipulating and retrieving information about chemical substances that distinguishes the techniques of chemical information handling from those of other disciplines. Chemical literature emphasizes the detailed structural characteristics of chemical substances. This is illustrated by the fact that for the 392,000 documents abstracted in 1975 in CHEMICAL ABSTRACTS, 1,514,000 chemical substance index entries were generated. Of these chemical substance index entries, 368,000 corresponded to substances which were reported for the first time in 1975. 

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